# Exception in wrapper.log: need explanation

**URL:** <https://forum.inductiveautomation.com/t/exception-in-wrapper-log-need-explanation/24873>\
**Category:** Ignition\
**Created:** [May 10, 2019, 7:46am UTC](https://forum.inductiveautomation.com/t/exception-in-wrapper-log-need-explanation/24873 "2019-05-10T07:46:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![pgmo](https://avatars.discourse-cdn.com/v4/letter/p/d07c76/32.png) [@pgmo](https://forum.inductiveautomation.com/u/pgmo)\
**Post date:** [May 10, 2019, 7:46am UTC](https://forum.inductiveautomation.com/t/exception-in-wrapper-log-need-explanation/24873/1 "2019-05-10T07:46:36Z")

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In a gateway wrapper.log I find many items like the following:

```auto
INFO | jvm 1 | 2019/05/02 11:11:43 | E [o.a.w.r.c.RequestCycle] [09:11:43]: Error during processing error message 
INFO | jvm 1 | 2019/05/02 11:11:43 | java.lang.IllegalStateException: Header was already written to response!

```

Any idea about that message?

Thanks in advance, regards

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<div class="post-metadata">

**Author:** ![chi](https://avatars.discourse-cdn.com/v4/letter/c/0ea827/32.png) [@chi](https://forum.inductiveautomation.com/u/chi)\
**Post date:** [May 10, 2019, 10:21am UTC](https://forum.inductiveautomation.com/t/exception-in-wrapper-log-need-explanation/24873/2 "2019-05-10T10:21:23Z")

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If this messages are logged when accessing the gateway webpages with Firefox it is a known bug that can be ignored. It is a problem in the underlying library.

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<div class="post-metadata">

**Author:** ![pgmo](https://avatars.discourse-cdn.com/v4/letter/p/d07c76/32.png) [@pgmo](https://forum.inductiveautomation.com/u/pgmo)\
**Post date:** [May 10, 2019, 6:56pm UTC](https://forum.inductiveautomation.com/t/exception-in-wrapper-log-need-explanation/24873/3 "2019-05-10T18:56:46Z")

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Thanks Mr chi. I cannot confirm at the moment that those messages are logged just when I access the gateway webpages with Firefox: I will pay attention at that.