# Classic UI Server Error **URL:** \ **Category:** Installation\ **Created:** [December 31, 2018, 1:40am UTC](https://community.openhab.org/t/classic-ui-server-error/61859 "2018-12-31T01:40:53Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Winsys11](https://community.openhab.org/letter_avatar_proxy/v4/letter/w/ed655f/32.png) [@Winsys11](https://community.openhab.org/u/Winsys11)\ **Post date:** [December 31, 2018, 1:40am UTC](https://community.openhab.org/t/classic-ui-server-error/61859/1 "2018-12-31T01:40:53Z")
I know this has been asked before, but I don’t see an answer anywhere. (other than clear the cache…) - Platform information: - Hardware: RP3 - openHAB version: 2.4.0 snapshot Classic UI and Paper UI do not work for me. Paper UI works fine, as does HABMIN If I reinstall the UI it still does not work if I clear the cache, _sometimes_ it works for a little while. this is the error message i get when trying to access Classic UI HTTP ERROR 500 Problem accessing /classicui/app. Reason: ``` Server Error ``` Caused by: java.lang.NullPointerException at org.eclipse.smarthome.ui.internal.items.ItemUIRegistryImpl.convertStateToWidgetUnit(ItemUIRegistryImpl.java:431) at org.eclipse.smarthome.ui.internal.items.ItemUIRegistryImpl.getLabel(ItemUIRegistryImpl.java:404) at org.eclipse.smarthome.ui.classic.internal.render.AbstractWidgetRenderer.getLabel(AbstractWidgetRenderer.java:126) at org.eclipse.smarthome.ui.classic.internal.render.AbstractWidgetRenderer.getLabel(AbstractWidgetRenderer.java:115) at org.eclipse.smarthome.ui.classic.internal.render.TextRenderer.renderWidget(TextRenderer.java:48) at org.eclipse.smarthome.ui.classic.internal.render.PageRenderer.renderWidget(PageRenderer.java:178) at org.eclipse.smarthome.ui.classic.internal.render.PageRenderer.processChildren(PageRenderer.java:139) at org.eclipse.smarthome.ui.classic.internal.render.PageRenderer.processChildren(PageRenderer.java:160) at org.eclipse.smarthome.ui.classic.internal.render.PageRenderer.processPage(PageRenderer.java:99) at org.eclipse.smarthome.ui.classic.internal.servlet.WebAppServlet.service(WebAppServlet.java:177) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:865) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:535) at org.ops4j.pax.web.service.jetty.internal.HttpServiceServletHandler.doHandle(HttpServiceServletHandler.java:71) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595) at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1317) at org.ops4j.pax.web.service.jetty.internal.HttpServiceContext.doHandle(HttpServiceContext.java:293) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564) at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1219) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144) at org.ops4j.pax.web.service.jetty.internal.JettyServerHandlerCollection.handle(JettyServerHandlerCollection.java:80) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132) at org.eclipse.jetty.server.Server.handle(Server.java:531) at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:352) at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:260) at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:281) at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102) at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:118) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168) at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126) at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:762) at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:680) at java.lang.Thread.run(Thread.java:748) any help appreciated. Happy New year to all. Mark ---
**Author:** ![vzorglub](https://community.openhab.org/user_avatar/community.openhab.org/vzorglub/32/17166_2.png) [@vzorglub](https://community.openhab.org/u/vzorglub)\ **Post date:** [December 31, 2018, 9:19am UTC](https://community.openhab.org/t/classic-ui-server-error/61859/2 "2018-12-31T09:19:12Z")
> [@Winsys11](#): > > convertStateToWidgetUnit It could be an error in your sitemap Please post the sitemap code, thanks ---
**Author:** ![Lolodomo](https://community.openhab.org/letter_avatar_proxy/v4/letter/l/ac91a4/32.png) [@Lolodomo](https://community.openhab.org/u/Lolodomo)\ **Post date:** [December 31, 2018, 9:59am UTC](https://community.openhab.org/t/classic-ui-server-error/61859/3 "2018-12-31T09:59:49Z")
Apparently relative to a channel using the ESH unit system. Maybe a wrong unit is set in the sitemap. ---
**Author:** ![Winsys11](https://community.openhab.org/letter_avatar_proxy/v4/letter/w/ed655f/32.png) [@Winsys11](https://community.openhab.org/u/Winsys11)\ **Post date:** [January 1, 2019, 12:51am UTC](https://community.openhab.org/t/classic-ui-server-error/61859/4 "2019-01-01T00:51:21Z")
hi, thanks for the replies. here’s my sitemap, it’s a work in progress… sitemap alma label=“Alma” { Frame label=“Weather” { Text item=Sunrise\_Sunset Text item=Sensor\_2\_temperature label=“Outside temperature [%.1f C]” icon=“temperature” Text item=Sensor\_2\_Luminance label=“Outside Luminance [%.1f]” icon=“sun” Text item=Sensor\_Smoke\_1\_temperature label=“Inside temperature [%.1f C]” icon=“temperature” Text item=Sensor\_Thermostat\_temperature label=“Thermo temperature [%.1f C]” icon=“temperature” } ``` Frame label="Control" { Group item=AllLights label="Lights" icon="light" { Frame label="Poolroom" { Switch item=Light_GF_Poolroom label="Lamp" icon="light" Colorpicker item=Light_GF_Poolroom_C label="Hue" Slider item=Light_GF_Poolroom_T label="Color Temperature" } Frame label="Lounge" { Switch item=Light_GF_Lounge label="Lamp" icon="light" Colorpicker item=Light_GF_Lounge_C label="Hue" Slider item=Light_GF_Lounge_T label="Color Temperature" } Frame label="Kitchen Cabinet" { Switch item=Light_GF_KitchenCabinet label="Lamp" icon="light" Colorpicker item=Light_GF_KitchenCabinet_C label="Hue" Slider item=Light_GF_KitchenCabinet_T label="Color Temperature" } Frame label="Bedroom" { Switch item=Light_GF_Bedroom label="Lamp" icon="light" Slider item=Light_GF_Bedroom_B label="Brightness" Slider item=Light_GF_Bedroom_T label="Color Temperature" } Frame label="Kitchen" { Switch item=Switch_GF_Kitchen label="Lamp" icon="light" } Frame label="External" { Switch item=Switch_GF_ExternalRear_Switch label="External Rear" icon="light" Switch item=Switch_GF_ExternalFront label="External Front" icon="light" Switch item=Switch_GF_ExternalParty label="Party Lights" icon="light" } } Group item=AllShutters label="Shutters" { Switch item=Shutter_GF_Poolroom mappings=[100="Close", 70="Half", 0="Open"] Switch item=Shutter_GF_MainBed mappings=[100="Close", 70="Half", 0="Open"] Switch item=Shutter_GF_SecondBed mappings=[100="Close", 70="Half", 0="Open"] Switch item=Shutter_GF_Laundry mappings=[100="Close", 70="Half", 0="Open"] } Group item=Windows label="Windows" { Switch item=Window_GF_Poolroom mappings=[0="Close", 50="Half", 100="Open"] Switch item=Window_GF_Lounge mappings=[0="Close", 50="Half", 100="Open"] } Group item=Media label="Media" { Switch item=LG_TV_Power label="TV Power" Switch item=MediaPC Switch item=LG_TV_Toast_Dummy Switch item=RXV773_Power label="Yamaha Power" Switch item=RXV773_Mute label="Yamaha Mute" Switch item=Thermostat_Clock label="Clock" Switch item=Scene_Media label="Media" Switch item=Fix_Clock label="Fix Clock" } Group item=HeatingCooling label="Heating / Cooling" { Text item=Sensor_Thermostat_temperature label="Room temperature [%.1f C]" icon="temperature" Selection item=Sensor_Thermostat_Mode label="Thermostat Mode [%d]" Selection item=Sensor_Thermostat_State label="Thermostat Setting" icon="gas" mappings=[0="Off",2="Heat",3="Cool",4="Auto",5="Resume"] Setpoint item=Sensor_Thermostat_Setpoint label="Set Point [%.1f C]" minValue=17 maxValue=24 step=0.5 } } Frame label="Status" { Group item=AllBatteries label="Batteries" icon="battery" { Text item=Sensor_Smoke_1_Battery label="Lounge Smoke Detector [%.1f]" icon="battery" Text item=Sensor_1_Battery label="Sensor 1 [%.1f]" icon="battery" Text item=Sensor_2_Battery label="Sensor 2 [%.1f]" icon="battery" } } ``` } ---
**Author:** ![Lolodomo](https://community.openhab.org/letter_avatar_proxy/v4/letter/l/ac91a4/32.png) [@Lolodomo](https://community.openhab.org/u/Lolodomo)\ **Post date:** [January 1, 2019, 10:51am UTC](https://community.openhab.org/t/classic-ui-server-error/61859/5 "2019-01-01T10:51:33Z")
Replace C by °C