[Solved] Cannot connect to OpenHAB dashboard on local network

[BrutalBirdie (Elias)]

Thanks I am going threw it, I will edit this post with my findings.

First

2019-12-20 00:42:09.656 [ERROR] [ui.internal.items.ItemUIRegistryImpl] - transformation throws exception [transformation=org.eclipse.smarthome.transform.map.internal.MapTransformationService@1c1227b, value=NIGHT]
org.eclipse.smarthome.core.transform.TransformationException: An error occurred while opening file.

Caused by: java.io.FileNotFoundException: /etc/openhab2/transform/astro.map (No such file or directory)

File /etc/openhab2/transform/astro.map seems missing.
This error is spamming quite a lot.

PS: Looks like you are ahead of my time

I think this is a point where you restarted openHAB, right?

2019-12-20 12:04:55.911 [INFO ] [basic.internal.servlet.WebAppServlet] - Stopped Basic UI
2019-12-20 12:05:02.671 [INFO ] [io.openhabcloud.internal.CloudClient] - Shutting down openHAB Cloud service connection
2019-12-20 12:05:02.708 [INFO ] [io.openhabcloud.internal.CloudClient] - Disconnected from the openHAB Cloud service (UUID = , base URL = http://localhost:8080)
2019-12-20 12:05:02.948 [INFO ] [assic.internal.servlet.WebAppServlet] - Stopped Classic UI
2019-12-20 12:05:02.976 [INFO ] [b.core.service.AbstractActiveService] - Expire Refresh Service has been shut down
2019-12-20 12:05:03.013 [INFO ] [ui.habmin.internal.servlet.HABminApp] - Stopped HABmin servlet
2019-12-20 12:05:04.086 [INFO ] [arthome.ui.paper.internal.PaperUIApp] - Stopped Paper UI
2019-12-20 12:05:04.134 [INFO ] [panel.internal.HABPanelDashboardTile] - Stopped HABPanel
2019-12-20 12:05:04.215 [INFO ] [.dashboard.internal.DashboardService] - Stopped Dashboard
2019-12-20 12:05:50.192 [INFO ] [panel.internal.HABPanelDashboardTile] - Started HABPanel at /habpanel
2019-12-20 12:05:50.303 [INFO ] [.core.internal.i18n.I18nProviderImpl] - Time zone set to 'Asia/Kolkata'.
2019-12-20 12:05:50.317 [INFO ] [.core.internal.i18n.I18nProviderImpl] - Location set to '17.4154514,78.5848738'.
2019-12-20 12:05:50.324 [INFO ] [.core.internal.i18n.I18nProviderImpl] - Locale set to 'en_IN'.
2019-12-20 12:05:54.318 [INFO ] [io.openhabcloud.internal.CloudClient] - Connected to the openHAB Cloud service (UUID = , base URL = http://localhost:8080)
2019-12-20 12:06:00.409 [INFO ] [el.core.internal.ModelRepositoryImpl] - Loading model 'basic.items'
2019-12-20 12:06:00.715 [INFO ] [el.core.internal.ModelRepositoryImpl] - Loading model 'astro.items'
2019-12-20 12:06:04.741 [INFO ] [thome.model.lsp.internal.ModelServer] - Started Language Server Protocol (LSP) service on port 5007
2019-12-20 12:06:05.402 [INFO ] [el.core.internal.ModelRepositoryImpl] - Loading model 'default.sitemap'
2019-12-20 12:06:05.944 [INFO ] [el.core.internal.ModelRepositoryImpl] - Validation issues found in configuration model 'basic.things', using it anyway:
Provide a thing type ID and a thing ID in this format:
 <thingTypeId> <thingId>
Provide a thing type ID and a thing ID in this format:
 <thingTypeId> <thingId>
Provide a thing type ID and a thing ID in this format:
 <thingTypeId> <thingId>
Provide a thing type ID and a thing ID in this format:
 <thingTypeId> <thingId>

Your basic.things file has erros.

019-12-20 12:06:05.957 [INFO ] [el.core.internal.ModelRepositoryImpl] - Loading model 'basic.things'
2019-12-20 12:06:06.229 [INFO ] [el.core.internal.ModelRepositoryImpl] - Loading model 'astro.things'
2019-12-20 12:06:07.369 [INFO ] [thome.binding.astro.internal.job.Job] - Scheduled Astro event-jobs for thing astro:sun:local
2019-12-20 12:06:07.519 [INFO ] [thome.binding.astro.internal.job.Job] - Scheduled Astro event-jobs for thing astro:moon:local
2019-12-20 12:06:07.541 [INFO ] [ding.astro.handler.AstroThingHandler] - Scheduled Positional job astro:moon:local every 300 seconds
2019-12-20 12:06:07.647 [WARN ] [mon.registry.AbstractManagedProvider] - Could not update element with key astro:sun:local in ManagedThingProvider, because it does not exists.
2019-12-20 12:06:07.651 [WARN ] [mon.registry.AbstractManagedProvider] - Could not update element with key astro:moon:local in ManagedThingProvider, because it does not exists.
2019-12-20 12:06:08.493 [INFO ] [.dashboard.internal.DashboardService] - Started Dashboard at http://192.168.31.53:8080
2019-12-20 12:06:08.498 [INFO ] [.dashboard.internal.DashboardService] - Started Dashboard at https://192.168.31.53:8443
2019-12-20 12:06:09.851 [INFO ] [arthome.ui.paper.internal.PaperUIApp] - Started Paper UI at /paperui
2019-12-20 12:06:09.986 [INFO ] [ui.habmin.internal.servlet.HABminApp] - Started HABmin servlet at /habmin
2019-12-20 12:06:10.343 [WARN ] [ore.common.registry.AbstractRegistry] - Cannot add "BridgeImpl" with key "mqtt:systemBroker:embedded-mqtt-broker". It exists already from provider "ManagedThingProvider"! Failed to add a second with the same UID from provider "GenericThingProvider"!
2019-12-20 12:06:11.352 [WARN ] [r.internal.EmbeddedBrokerServiceImpl] - Embedded broker offline - Reason unknown
2019-12-20 12:06:11.504 [INFO ] [.transport.mqtt.MqttBrokerConnection] - Starting MQTT broker connection to '127.0.0.1' with clientid embedded-mqtt-broker and file store '/var/lib/openhab2/mqtt/127.0.0.1'
2019-12-20 12:06:11.599 [ERROR] [el.item.internal.GenericItemProvider] - Binding configuration of type 'expire' of item 'Livingroom_TV_Power' could not be parsed correctly.
org.eclipse.smarthome.model.item.BindingConfigParseException: The string '0' does not represent a valid state for item Livingroom_TV_Power

2019-12-20 12:06:08.493 [INFO ] [.dashboard.internal.DashboardService] - Started Dashboard at http://192.168.31.53:8080
2019-12-20 12:06:08.498 [INFO ] [.dashboard.internal.DashboardService] - Started Dashboard at https://192.168.31.53:8443
2019-12-20 12:06:09.851 [INFO ] [arthome.ui.paper.internal.PaperUIApp] - Started Paper UI at /paperui
2019-12-20 12:06:09.986 [INFO ] [ui.habmin.internal.servlet.HABminApp] - Started HABmin servlet at /habmin

Web Server started.

2019-12-20 12:06:10.343 [WARN ] [ore.common.registry.AbstractRegistry] - Cannot add "BridgeImpl" with key "mqtt:systemBroker:embedded-mqtt-broker". It exists already from provider "ManagedThingProvider"! Failed to add a second with the same UID from provider "GenericThingProvider"!
2019-12-20 12:06:11.352 [WARN ] [r.internal.EmbeddedBrokerServiceImpl] - Embedded broker offline - Reason unknown

This seems off, do you use an external mqtt broker and an embedded one?

2019-12-20 12:06:11.504 [INFO ] [.transport.mqtt.MqttBrokerConnection] - Starting MQTT broker connection to '127.0.0.1' with clientid embedded-mqtt-broker and file store '/var/lib/openhab2/mqtt/127.0.0.1'
2019-12-20 12:06:11.599 [ERROR] [el.item.internal.GenericItemProvider] - Binding configuration of type 'expire' of item 'Livingroom_TV_Power' could not be parsed correctly.
org.eclipse.smarthome.model.item.BindingConfigParseException: The string '0' does not represent a valid state for item Livingroom_TV_Power

Wrong state, you should investigate this.

TL;DR

You openHAB is starting and stopping quite a lot. (¿Bootloop?)
I would advice looking into the errors.
Did you try clearing the cache?

Clear the Cache

Often when one encounters a problem with OH, particularly after an update, OH will refuse to run or certain parts of OH stop working. Some reported errors include: 500 or 404 errors when accessing the UIs lots of exceptions from Jetty or other core components in openhab.log OH refuses to start at all The first step in debugging the problem is to clear the tmp and cache. Installed OH If you are running an installed OH (openHABian, installed using apt or yum): openhab-cli stop openhab-cl…