Can't reach OH2 web interface any more, SSH, samba is working

This night my OH suddenly stopped working. It is reachable through putty and through samba, but the actual functionaltiy is dead.
Yesterday I had a random view through putty in my working system, where I could see OH has been online for 76 days and this night it ust stopped working.
My OH 2.3 stable version runs on a RPI 3 with a SSD.
sudo /bin/systemctl status openhab2.service gives me:

[sudo] password for openhabian:
● openhab2.service - openHAB 2 - empowering the smart home
   Loaded: loaded (/usr/lib/systemd/system/openhab2.service; enabled; vendor preset: enabled)
   Active: activating (auto-restart) (Result: exit-code) since Mon 2018-08-13 19:54:11 CEST; 3s ago
     Docs: https://www.openhab.org/docs/
           https://community.openhab.org
  Process: 14431 ExecStop=/usr/share/openhab2/runtime/bin/karaf stop (code=exited, status=1/FAILURE)
  Process: 14310 ExecStart=/usr/share/openhab2/runtime/bin/karaf $OPENHAB_STARTMODE (code=exited, status=1/FAILURE)
 Main PID: 14310 (code=exited, status=1/FAILURE)

Aug 13 19:54:11 openHABianPi systemd[1]: openhab2.service: Failed with result 'exit-code'.

and the OH.log says INMO nothing relevant about the Failure, but stuff like:

2018-08-13 18:49:00.583 [INFO ] [el.core.internal.ModelRepositoryImpl] - Refreshing model 'Anderes.items'
2018-08-13 18:49:00.767 [INFO ] [el.core.internal.ModelRepositoryImpl] - Refreshing model 'Alarmanlage.items'
2018-08-13 18:49:01.638 [INFO ] [el.core.internal.ModelRepositoryImpl] - Refreshing model 'heizplan.rules'
2018-08-13 18:49:01.648 [ERROR] [xbase.resource.BatchLinkableResource] - resolution of uriFragment '|::0.1.0.1::1::/0' failed.
org.eclipse.xtext.util.RuntimeIOException: java.io.FileNotFoundException: /var/lib/openhab2/heizplan.rules (No such file or directory)
	at org.eclipse.xtext.resource.DerivedStateAwareResourceDescriptionManager.internalGetResourceDescription(DerivedStateAwareResourceDescriptionManager.java:47) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.resource.impl.DefaultResourceDescriptionManager$1.get(DefaultResourceDescriptionManager.java:62) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.resource.impl.DefaultResourceDescriptionManager$1.get(DefaultResourceDescriptionManager.java:59) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.util.OnChangeEvictingCache.get(OnChangeEvictingCache.java:77) [155:org.eclipse.xtext.util:2.12.0.v20170518-0959]
	at org.eclipse.xtext.resource.impl.DefaultResourceDescriptionManager.getResourceDescription(DefaultResourceDescriptionManager.java:59) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.resource.persistence.StorageAwareResourceDescriptionManager.getResourceDescription(StorageAwareResourceDescriptionManager.java:35) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.resource.impl.ResourceSetBasedResourceDescriptions.getResourceDescription(ResourceSetBasedResourceDescriptions.java:120) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.resource.impl.ResourceSetBasedResourceDescriptions$1$1.computeNext(ResourceSetBasedResourceDescriptions.java:74) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.resource.impl.ResourceSetBasedResourceDescriptions$1$1.computeNext(ResourceSetBasedResourceDescriptions.java:64) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143) [23:com.google.guava:18.0.0]
	at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138) [23:com.google.guava:18.0.0]
	at com.google.common.collect.Iterators$7.computeNext(Iterators.java:650) [23:com.google.guava:18.0.0]
	at com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143) [23:com.google.guava:18.0.0]
	at com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138) [23:com.google.guava:18.0.0]
	at com.google.common.collect.TransformedIterator.hasNext(TransformedIterator.java:43) [23:com.google.guava:18.0.0]
	at com.google.common.collect.TransformedIterator.hasNext(TransformedIterator.java:43) [23:com.google.guava:18.0.0]
	at com.google.common.collect.Iterators$5.hasNext(Iterators.java:547) [23:com.google.guava:18.0.0]
	at org.eclipse.xtext.common.types.access.impl.IndexedJvmTypeAccess.getIndexedJvmType(IndexedJvmTypeAccess.java:109) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.access.impl.IndexedJvmTypeAccess.getIndexedJvmType(IndexedJvmTypeAccess.java:101) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.access.impl.AbstractRuntimeJvmTypeProvider.doTryFindInIndex(AbstractRuntimeJvmTypeProvider.java:105) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.access.impl.AbstractRuntimeJvmTypeProvider.doTryFindInIndex(AbstractRuntimeJvmTypeProvider.java:85) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.access.impl.AbstractRuntimeJvmTypeProvider$TypeInResourceSetAdapter.tryFindTypeInIndex(AbstractRuntimeJvmTypeProvider.java:51) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.access.impl.AbstractRuntimeJvmTypeProvider.tryFindTypeInIndex(AbstractRuntimeJvmTypeProvider.java:115) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.access.reflect.ReflectionTypeProvider.doFindTypeByName(ReflectionTypeProvider.java:128) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.access.reflect.ReflectionTypeProvider.findTypeByName(ReflectionTypeProvider.java:109) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.xtext.AbstractTypeScope.getSingleElement(AbstractTypeScope.java:59) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.xtext.AbstractTypeScope.getSingleElement(AbstractTypeScope.java:54) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.xtext.AbstractTypeScope.getElements(AbstractTypeScope.java:73) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.scoping.impl.AbstractScope.getElements(AbstractScope.java:137) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.scoping.impl.ScopeBasedSelectable.getExportedObjects(ScopeBasedSelectable.java:40) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.scoping.impl.ImportScope.getLocalElementsByName(ImportScope.java:154) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.scoping.impl.ImportScope.getSingleLocalElementByName(ImportScope.java:142) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.scoping.impl.AbstractScope.getSingleElement(AbstractScope.java:105) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.scoping.impl.AbstractScope.getSingleElement(AbstractScope.java:108) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.scoping.impl.AbstractScope.getSingleElement(AbstractScope.java:108) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.linking.impl.DefaultLinkingService.getLinkedObjects(DefaultLinkingService.java:122) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.linking.lazy.LazyLinkingResource.getEObject(LazyLinkingResource.java:247) [152:org.eclipse.xtext:2.12.0.v20170518-0959]
	at org.eclipse.xtext.xbase.resource.BatchLinkableResource.getEObject(BatchLinkableResource.java:119) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.emf.ecore.resource.impl.ResourceSetImpl.getEObject(ResourceSetImpl.java:223) [68:org.eclipse.emf.ecore:2.11.1.v20150805-0538]
	at org.eclipse.emf.ecore.util.EcoreUtil.resolve(EcoreUtil.java:199) [68:org.eclipse.emf.ecore:2.11.1.v20150805-0538]
	at org.eclipse.emf.ecore.util.EcoreUtil.resolve(EcoreUtil.java:259) [68:org.eclipse.emf.ecore:2.11.1.v20150805-0538]
	at org.eclipse.emf.ecore.impl.BasicEObjectImpl.eResolveProxy(BasicEObjectImpl.java:1477) [68:org.eclipse.emf.ecore:2.11.1.v20150805-0538]
	at org.eclipse.xtext.common.types.impl.JvmTypeReferenceImplCustom.eResolveProxy(JvmTypeReferenceImplCustom.java:31) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.impl.JvmParameterizedTypeReferenceImpl.getType(JvmParameterizedTypeReferenceImpl.java:111) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.references.LightweightTypeReferenceFactory.getType(LightweightTypeReferenceFactory.java:242) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.references.LightweightTypeReferenceFactory.doVisitParameterizedTypeReference(LightweightTypeReferenceFactory.java:173) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.references.LightweightTypeReferenceFactory.doVisitParameterizedTypeReference(LightweightTypeReferenceFactory.java:52) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.impl.JvmParameterizedTypeReferenceImplCustom.accept(JvmParameterizedTypeReferenceImplCustom.java:53) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.common.types.util.AbstractTypeReferenceVisitor.visit(AbstractTypeReferenceVisitor.java:34) [153:org.eclipse.xtext.common.types:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.references.LightweightTypeReferenceFactory.toLightweightReference(LightweightTypeReferenceFactory.java:83) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.references.StandardTypeReferenceOwner.toLightweightTypeReference(StandardTypeReferenceOwner.java:117) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.LogicalContainerAwareReentrantTypeResolver._doPrepare(LogicalContainerAwareReentrantTypeResolver.java:538) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.LogicalContainerAwareReentrantTypeResolver.doPrepare(LogicalContainerAwareReentrantTypeResolver.java:463) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.LogicalContainerAwareReentrantTypeResolver.prepareMembers(LogicalContainerAwareReentrantTypeResolver.java:500) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.LogicalContainerAwareReentrantTypeResolver._doPrepare(LogicalContainerAwareReentrantTypeResolver.java:471) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.LogicalContainerAwareReentrantTypeResolver.doPrepare(LogicalContainerAwareReentrantTypeResolver.java:459) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.LogicalContainerAwareReentrantTypeResolver.prepare(LogicalContainerAwareReentrantTypeResolver.java:409) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.LogicalContainerAwareReentrantTypeResolver.computeTypes(LogicalContainerAwareReentrantTypeResolver.java:696) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.DefaultReentrantTypeResolver.resolve(DefaultReentrantTypeResolver.java:163) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.DefaultReentrantTypeResolver.reentrantResolve(DefaultReentrantTypeResolver.java:139) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.CachingBatchTypeResolver$LazyResolvedTypes.resolveTypes(CachingBatchTypeResolver.java:80) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.CachingBatchTypeResolver$2.process(CachingBatchTypeResolver.java:57) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.CachingBatchTypeResolver$2.process(CachingBatchTypeResolver.java:53) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.util.concurrent.IUnitOfWork$Void.exec(IUnitOfWork.java:37) [155:org.eclipse.xtext.util:2.12.0.v20170518-0959]
	at org.eclipse.xtext.util.OnChangeEvictingCache.execWithoutCacheClear(OnChangeEvictingCache.java:129) [155:org.eclipse.xtext.util:2.12.0.v20170518-0959]
	at org.eclipse.xtext.xbase.typesystem.internal.CachingBatchTypeResolver.doResolveTypes(CachingBatchTypeResolver.java:53) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.AbstractBatchTypeResolver.resolveTypes(AbstractBatchTypeResolver.java:69) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.typesystem.internal.AbstractBatchTypeResolver.resolveTypes(AbstractBatchTypeResolver.java:55) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter._doEvaluate(XbaseInterpreter.java:306) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.doEvaluate(XbaseInterpreter.java:249) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.smarthome.model.script.interpreter.ScriptInterpreter.doEvaluate(ScriptInterpreter.java:219) [137:org.eclipse.smarthome.model.script:0.10.0.oh230]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.internalEvaluate(XbaseInterpreter.java:203) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.xtext.xbase.interpreter.impl.XbaseInterpreter.evaluate(XbaseInterpreter.java:189) [156:org.eclipse.xtext.xbase:2.12.0.v20170519-0752]
	at org.eclipse.smarthome.model.script.runtime.internal.engine.ScriptImpl.execute(ScriptImpl.java:82) [139:org.eclipse.smarthome.model.script.runtime:0.10.0.oh230]
	at org.eclipse.smarthome.model.script.runtime.internal.engine.ScriptImpl.execute(ScriptImpl.java:63) [139:org.eclipse.smarthome.model.script.runtime:0.10.0.oh230]
	at org.eclipse.smarthome.model.rule.runtime.internal.engine.RuleContextHelper.getContext(RuleContextHelper.java:64) [136:org.eclipse.smarthome.model.rule.runtime:0.10.0.oh230]
	at org.eclipse.smarthome.model.rule.runtime.internal.engine.ExecuteRuleJob.execute(ExecuteRuleJob.java:67) [136:org.eclipse.smarthome.model.rule.runtime:0.10.0.oh230]
	at org.quartz.core.JobRunShell.run(JobRunShell.java:202) [107:org.eclipse.smarthome.core.scheduler:0.10.0.oh230]
	at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573) [107:org.eclipse.smarthome.core.scheduler:0.10.0.oh230]
Caused by: java.io.FileNotFoundException: /var/lib/openhab2/heizplan.rules (No such file or directory)
	at java.io.FileInputStream.open0(Native Method) ~[?:?]
	at java.io.FileInputStream.open(FileInputStream.java:195) ~[?:?]
	at java.io.FileInputStream.<init>(FileInputStream.java:138) ~[?:?]
	at org.eclipse.emf.ecore.resource.impl.FileURIHandlerImpl.createInputStream(FileURIHandlerImpl.java:99) ~[?:?]
	at org.eclipse.emf.ecore.resource.impl.ExtensibleURIConverterImpl.createInputStream(ExtensibleURIConverterImpl.java:360) ~[?:?]
	at org.eclipse.xtext.resource.XtextResourceSet$1.createInputStream(XtextResourceSet.java:298) ~[?:?]
	at org.eclipse.emf.ecore.resource.impl.ResourceImpl.load(ResourceImpl.java:1269) ~[?:?]
	at org.eclipse.xtext.resource.persistence.StorageAwareResource.load(StorageAwareResource.java:80) ~[?:?]
	at org.eclipse.xtext.resource.DerivedStateAwareResourceDescriptionManager.internalGetResourceDescription(DerivedStateAwareResourceDescriptionManager.java:45) ~[?:?]
	... 78 more

heizplan.rules didnt change and is still in my rules folder since I created it last year. So dont understand this weired file not found error. My guess is that its just a result of a different failure in OH.

Solved with clearing the cache:

sudo /etc/init.d/openhab2 stop
sudo rm -rf /var/lib/openhab2/cache/*
sudo rm -rf /var/lib/openhab2/tmp/*
sudo /etc/init.d/openhab2 start

The reason for that issue is still unknown though.