# Unable to Connect to OPC wrapper

**URL:** <https://forum.inductiveautomation.com/t/unable-to-connect-to-opc-wrapper/8633>\
**Category:** Ignition\
**Created:** [June 27, 2014, 11:26am UTC](https://forum.inductiveautomation.com/t/unable-to-connect-to-opc-wrapper/8633 "2014-06-27T11:26:24Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Viggi](https://avatars.discourse-cdn.com/v4/letter/v/ce7236/32.png) [@Viggi](https://forum.inductiveautomation.com/u/Viggi)\
**Post date:** [June 27, 2014, 11:26am UTC](https://forum.inductiveautomation.com/t/unable-to-connect-to-opc-wrapper/8633/1 "2014-06-27T11:26:24Z")

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Hi!..

I am trying to connect to Matrikon OPC UA wrapper, which has wrapped my legacy OPC server.  
I am using Ignition on LInux.  
I followed the instructions given, as per my previous post…  
[http://inductiveautomation.com/forum/viewtopic.php?f=70&t=10376&p=37038&hilit=host+override#p37038](http://inductiveautomation.com/forum/viewtopic.php?f=70&t=10376&p=37038&hilit=host+override#p37038)  
.  
I am getting connection status : Unknown…  
when i check the error log i get the following error.  
java.lang.NullPointerExecption.

Looking forward to a solution.

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<div class="post-metadata">

**Author:** ![Colby.Clegg](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/colby.clegg/32/3282_2.png) [@Colby.Clegg](https://forum.inductiveautomation.com/u/Colby.Clegg)\
**Post date:** [July 1, 2014, 3:20pm UTC](https://forum.inductiveautomation.com/t/unable-to-connect-to-opc-wrapper/8633/2 "2014-07-01T15:20:49Z")

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Hi,

Can you perhaps export the error log from the console and post it here? We might be able to get a better sense of what’s going on.

Regards,

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<div class="post-metadata">

**Author:** ![Viggi](https://avatars.discourse-cdn.com/v4/letter/v/ce7236/32.png) [@Viggi](https://forum.inductiveautomation.com/u/Viggi)\
**Post date:** [July 15, 2014, 4:29pm UTC](https://forum.inductiveautomation.com/t/unable-to-connect-to-opc-wrapper/8633/3 "2014-07-15T16:29:16Z")

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Hi,

Could you tell me where the error log file is stored ?

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<div class="post-metadata">

**Author:** ![Colby.Clegg](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/colby.clegg/32/3282_2.png) [@Colby.Clegg](https://forum.inductiveautomation.com/u/Colby.Clegg)\
**Post date:** [July 15, 2014, 4:42pm UTC](https://forum.inductiveautomation.com/t/unable-to-connect-to-opc-wrapper/8633/4 "2014-07-15T16:42:27Z")

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Hi,

If you log into the gateway, and go to “Configuration”, and then click on “Console” on the left hand side, you should then see the running log. At the top right, there is a link to export it. That exports a binary format that we can look at here.

Otherwise, the plain text version is stored in “{InstallDir}\logs” in files called “wrapper.log”. They both generally have the same information, but the “wrapper.log” sometimes have additional information concerning the startup/shutdown of Ignition.

Regards,