# V8.1.0 Null pointer exception in OPC Server diagnostics for Rx3i PLC **URL:** \ **Category:** Ignition\ **Tags:** ignition80\ **Created:** [December 9, 2020, 5:15pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347 "2020-12-09T17:15:21Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [December 9, 2020, 5:15pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/1 "2020-12-09T17:15:21Z")
This is on a fresh install of v8.1.0 running on Ubuntu (and running on a VirtualBox VM) I just made an OPC connection to my local Rx3i CPE305 based system. On the gateway the status is marked as "Connected", but when I click on the "Server Diagnostics" I get an error message for a Null pointer exception: > Error { "servlet":"DataRoutes", "message":"java.lang.NullPointerException: diagObjectBrowse.references must not be null", "url":"/data/opc-ua/status/diagnostics/TESTLOCALPLC1/sessions", "status":"500" } Note: 1. I get valid data when I clicked on the Server Diagnostics for the Ignition OPC UA Server 2. I can successfully connect to the same PLC using the free Matrikon OPC UA Explorer and see all sorts of diagnostic data there Here are some pretty pictures of my setup and the issue: ![Ignition System](https://us1.discourse-cdn.com/inductiveautomation/original/3X/5/c/5c8bff293a80e92b295b07b727c5d316916169d9.png) ![OPC Connections](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/e/8e8966837a502c20d98669e597074a6afe3ffbdb.png) ![Error Message](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/d/edff62bf4fa769301a3916a63ca7916dfe13fb95.png) ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [December 9, 2020, 5:23pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/2 "2020-12-09T17:23:53Z")
Thanks, I think this is probably easy to fix. If I build and upload an OPC UA module in a bit here would you be able to verify the fix against this server? ---
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [December 9, 2020, 5:24pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/3 "2020-12-09T17:24:52Z")
Yes I am happy to help to get things fixed! ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [December 9, 2020, 6:00pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/4 "2020-12-09T18:00:38Z")
Okay, try installing [this OPC UA module](https://www.dropbox.com/s/1ad60vme8y99tn4/OPC-UA-module.modl?dl=0) and see if anything changes. ---
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [December 9, 2020, 6:11pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/5 "2020-12-09T18:11:04Z")
That fixed the problem ![Fixed](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/6/1682a344e0d23c9cabdb1e4a53df9d9355147bfc.png) ---
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [December 9, 2020, 6:14pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/6 "2020-12-09T18:14:08Z")
Now for the big question. When will this fix likely make it to an official release? ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [December 9, 2020, 6:15pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/7 "2020-12-09T18:15:07Z")
It will be part of 8.1.2. A nightly release that is basically no more official than the module I just gave you will be available sooner, but the final release of 8.1.2 is sometime in January. ---
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [December 9, 2020, 6:17pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/8 "2020-12-09T18:17:45Z")
I have a customer deadline for the end of January … so that should work out great! Now I’m going to surprise my colleagues (again!) with the fact that I reported and got a solution to a genuine bug in an hour. Not like some other HMI providers that work at a glacial pace 😉 ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [December 9, 2020, 6:18pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/9 "2020-12-09T18:18:27Z")
> [@peter](#): > > Now I’m going to surprise my colleagues (again!) with the fact that I reported and got a solution to a genuine bug in an hour. Sometimes you get lucky, other times not as much... 🙂 ---
**Author:** ![Kiriakos.Kalpakidis](https://avatars.discourse-cdn.com/v4/letter/k/f19dbf/32.png) [@Kiriakos.Kalpakidis](https://forum.inductiveautomation.com/u/Kiriakos.Kalpakidis)\ **Post date:** [December 11, 2020, 5:37pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/10 "2020-12-11T17:37:52Z")
I’m currently having the exact same error with 8.0.16 and a Van Dorn (Injection Molding Machine) which runs an S3 (SigmaTek) OPC-UA server. Coincidentally enough, we started having issues with the subscription dropping and the server refusing to forward the sub. I’m admittedly out of my depth on most of this. Thanks in advance ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [December 11, 2020, 5:42pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/11 "2020-12-11T17:42:12Z")
I don’t think the two things are related. You’ll have to upgrade to 8.1.1 if you want to test this module and see if it allows you to access the status page. Troubleshooting the subscription dropping will require a bit more information: logs, maybe Wireshark captures, etc… and is probably more appropriate for a new topic. ---
**Author:** ![Kiriakos.Kalpakidis](https://avatars.discourse-cdn.com/v4/letter/k/f19dbf/32.png) [@Kiriakos.Kalpakidis](https://forum.inductiveautomation.com/u/Kiriakos.Kalpakidis)\ **Post date:** [December 11, 2020, 5:49pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/12 "2020-12-11T17:49:45Z")
Thanks for the quick reply. I will start a new topic if the issue persists over the weekend. ---
**Author:** ![Nirav\_Darji](https://avatars.discourse-cdn.com/v4/letter/n/85e7bf/32.png) [@Nirav\_Darji](https://forum.inductiveautomation.com/u/Nirav_Darji)\ **Post date:** [September 3, 2024, 5:52pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/13 "2024-09-03T17:52:43Z")
Hi, I have the same issue in the 8.1.41 version. Data are not updating for 2-3 hours and after that data will update. I have restarted the OPC UA module and after that data are updating. Can you please suggest me what to do on this? Thanks ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [September 3, 2024, 5:55pm UTC](https://forum.inductiveautomation.com/t/v8-1-0-null-pointer-exception-in-opc-server-diagnostics-for-rx3i-plc/41347/14 "2024-09-03T17:55:29Z")
This was originally about a problem with the status/diagnostics page. If your problem is something else start a new topic and explain your issue in detail.