# Error fetching groups.java.lang.NullPointerException **URL:** \ **Category:** Ignition\ **Tags:** ignition79\ **Created:** [March 19, 2020, 12:13pm UTC](https://forum.inductiveautomation.com/t/error-fetching-groups-java-lang-nullpointerexception/33236 "2020-03-19T12:13:05Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![edo](https://avatars.discourse-cdn.com/v4/letter/e/e5b9ba/32.png) [@edo](https://forum.inductiveautomation.com/u/edo)\ **Post date:** [March 19, 2020, 12:13pm UTC](https://forum.inductiveautomation.com/t/error-fetching-groups-java-lang-nullpointerexception/33236/1 "2020-03-19T12:13:05Z")
Hi, I have the problem with Datatype variable. I created a datatype and I used it for 5 componente (same variables inside the PLCs) but I do not have the same results. I do not see all variabiles and I have this error in the logs of Ignition: “Error fetching groups.java.lang.NullPointerException” In the image below you can see the comportament. ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/c/c69bc1cba759385c921eef7fe8f6de01f00880f6.png) Can you help me? I use the OPC-UA protocol. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [March 19, 2020, 12:17pm UTC](https://forum.inductiveautomation.com/t/error-fetching-groups-java-lang-nullpointerexception/33236/2 "2020-03-19T12:17:52Z")
Please show the complete error with backtrace. Don’t use a screenshot. Instead, copy the text from the wrapper log and paste it here. Use triple backquotes (these: ```) on a line above and again below the pasted text so it will be formatted in a code block. Also show the OPC Item Path for the affected tags. ---
**Author:** ![edo](https://avatars.discourse-cdn.com/v4/letter/e/e5b9ba/32.png) [@edo](https://forum.inductiveautomation.com/u/edo)\ **Post date:** [March 19, 2020, 12:28pm UTC](https://forum.inductiveautomation.com/t/error-fetching-groups-java-lang-nullpointerexception/33236/3 "2020-03-19T12:28:05Z")
This is the logs > Blockquote | Wrapper | 19Mar2020 13:20:35 | Error fetching groups.java.lang.NullPointerException | | --- | --- | --- | | Wrapper | 19Mar2020 13:20:35 | Error fetching users.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:19:16 | Error fetching groups.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:19:16 | Error fetching users.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:18:02 | Error fetching groups.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:18:02 | Error fetching users.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:16:50 | Error fetching groups.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:16:50 | Error fetching users.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:15:33 | Error fetching groups.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:15:33 | Error fetching users.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:14:18 | Error fetching groups.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:14:18 | Error fetching users.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:12:03 | Error fetching groups.java.lang.NullPointerException | | Wrapper | 19Mar2020 13:12:03 | Error fetching users.java.lang.NullPointerException | > Blockquote This is the variables path. ns=6;s=::AsGlobalPV:Generatore[5].dig\_inp.PressioneAria I tried to create with this path a new OPC tag and this work. You can see below ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/b/b201e22ea771e59e15e935c5c2537fb98f846040.png) I do not understand why inside the datatype it do not work. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [March 19, 2020, 1:11pm UTC](https://forum.inductiveautomation.com/t/error-fetching-groups-java-lang-nullpointerexception/33236/4 "2020-03-19T13:11:16Z")
I don't think the error fetching groups/users is relevant. That looks like some other problem, happening every couple minutes or so. I can't tell what's wrong with the affected elements of the UDT.... you'll have to carefully compare every property against the corresponding property of a working tag. Consider exporting in XML format (one working, one non-working) and posting here as a code block. (Please use the triple back-quotes as requested--not the blockquote function.) ---
**Author:** ![edo](https://avatars.discourse-cdn.com/v4/letter/e/e5b9ba/32.png) [@edo](https://forum.inductiveautomation.com/u/edo)\ **Post date:** [March 23, 2020, 9:52am UTC](https://forum.inductiveautomation.com/t/error-fetching-groups-java-lang-nullpointerexception/33236/5 "2020-03-23T09:52:50Z")
I found the problem. The Datatype variables do not support if you insert much OPC tags not defined inside it. Now I defined all variables and it work.