# Problem when re-connecting VCN Viewer to ursim

**URL:** <https://forum.universal-robots.com/t/problem-when-re-connecting-vcn-viewer-to-ursim/27098>\
**Category:** Technical Questions\
**Created:** [March 1, 2023, 9:10pm UTC](https://forum.universal-robots.com/t/problem-when-re-connecting-vcn-viewer-to-ursim/27098 "2023-03-01T21:10:34Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![tomaszdrewniak](https://avatars.discourse-cdn.com/v4/letter/t/ee59a6/32.png) [@tomaszdrewniak](https://forum.universal-robots.com/u/tomaszdrewniak)\
**Post date:** [March 1, 2023, 9:10pm UTC](https://forum.universal-robots.com/t/problem-when-re-connecting-vcn-viewer-to-ursim/27098/1 "2023-03-01T21:10:34Z")

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System

- windows 10
- ursim running in docker (UR 10)
- VNC Viewer (connecting on port 5900, localhost)  
After I start ursim I can connect to it using VCN Viewer, work on it and so on

There are cases, when VNC viewer drops the connection, after that I can not re-connect to ursim, getting an error “Connection closed unexpectedly”.

The only way to fix it (that I know off) is to restart ursim docker container. Once this is done I can connect again.  
just FYI - ursim is working, I know that program is running (I am sending data out)

Any idea how to fix it witout restarting ursim docker container

Thanks, Tomasz

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**Author:** ![sam.verity-hilton](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.universal-robots.com/sam.verity-hilton/32/6046_2.png) [@sam.verity-hilton](https://forum.universal-robots.com/u/sam.verity-hilton)\
**Post date:** [March 2, 2023, 10:01am UTC](https://forum.universal-robots.com/t/problem-when-re-connecting-vcn-viewer-to-ursim/27098/2 "2023-03-02T10:01:48Z")

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try watching the polyscpe log when you have the container running, if it crashes, you should be able to check the log and see what problem has occurred, this may help provide some mroe info on what is happening. I’ve not seen this happen myself, but haven’t run many programs in my docker container

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<div class="post-metadata">

**Author:** ![tomaszdrewniak](https://avatars.discourse-cdn.com/v4/letter/t/ee59a6/32.png) [@tomaszdrewniak](https://forum.universal-robots.com/u/tomaszdrewniak)\
**Post date:** [March 30, 2023, 8:39pm UTC](https://forum.universal-robots.com/t/problem-when-re-connecting-vcn-viewer-to-ursim/27098/3 "2023-03-30T20:39:59Z")

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This is what I got from the polscope log:  
OPC UA daemon status: RUNNING  
OPC UA runningState changed from -1 to 0  
setServerRunningState: true  
setServerRunningState: trying to start server  
setServerRunningState: serverStart true  
OPC UA runningState changed from 0 to 1

2023-03-30 16:13:24.628 ERROR - RobotState messages are queued up: 59 {thread: RobotState - PostMan , loggerClass: com.ur.monitor.RobotState$PostMan}  
2023-03-30 16:15:32.702 ERROR - File attachment not found: /tmp/log/urcontrol/current {thread: pool-12-thread-1 , loggerClass: com.ur.polyscope.flightrecorder.internal.attachment.FlightRecorderTextFileAttachment}  
2023-03-30 16:16:32.369 ERROR - File attachment not found: /tmp/log/urcontrol/current {thread: pool-12-thread-1 , loggerClass: com.ur.polyscope.flightrecorder.internal.attachment.FlightRecorderTextFileAttachment}  
2023-03-30 20:48:26.738 ERROR - File attachment not found: /tmp/log/urcontrol/current {thread: pool-12-thread-1 , loggerClass: com.ur.polyscope.flightrecorder.internal.attachment.FlightRecorderTextFileAttachment}  
re queued up: 59 {thread: RobotState - PostMan , loggerClass: com.ur.monitor.RobotState$PostMan}  
2023-03-30 16:15:32.702 ERROR - File attachment not found: /tmp/log/urcontrol/current {thread: pool-12-thread-1 , loggerClass: com.ur.polyscope.flightrecorder.internal.attachment.FlightRecorderTextFileAttachment}  
2023-03-30 16:16:32.369 ERROR - File attachment not found: /tmp/log/urcontrol/current {thread: pool-12-thread-1 , loggerClass: com.ur.polyscope.flightrecorder.internal.attachment.FlightRecorderTextFileAttachment}

Question - is there a way to recover from that without restarting container ?