# "400 Bad Request" error after upgrading
**URL:** https://meta.discourse.org/t/400-bad-request-error-after-upgrading/175277
**Category:** Support
**Created:** [January 6, 2021, 3:49pm UTC](https://meta.discourse.org/t/400-bad-request-error-after-upgrading/175277 "2021-01-06T15:49:29Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@ggurbet](https://meta.discourse.org/u/ggurbet)
#### Post date: [January 6, 2021, 3:49pm UTC](https://meta.discourse.org/t/400-bad-request-error-after-upgrading/175277/1 "2021-01-06T15:49:29Z")
Hello. I have [upgraded](https://meta.discourse.org/t/how-do-i-manually-update-discourse-and-docker-image-to-latest/23325) our forum from v2.3.0.beta5 to latest and now the website gives a [“400 Bad Request”](https://forum.pardus.org.tr/) upon reaching it.
If I rebuild the app, as soon as the container is stopped, server gives a “502 Bad Gateway” error. But after finishing the rebuild and starting the container, error 400 appears again.
I was not responsible for the forum for a while so the upgrade was done very late. The forum only has official plugins. I have disabled some of them and rebuild the app to no avail. Do you have any ideas about the cause and how to fix the problem? Thanks in advance.
Edit: Some warnings I got:
```plaintext
I, [2021-01-06T16:46:07.011565 #1] INFO -- : > cd /var/www/discourse && find /var/www/discourse ! -user discourse -exec chown discourse {} \+
I, [2021-01-06T16:46:10.379601 #1] INFO -- :
I, [2021-01-06T16:46:10.380578 #1] INFO -- : > cd /var/www/discourse && su discourse -c 'bundle install --deployment --retry 3 --jobs 4 --verbose --without test development'
[DEPRECATED] The `--deployment` flag is deprecated because it relies on being remembered across bundler invocations, which bundler will no longer do in future versions. Instead please use `
bundle config set --local deployment 'true'`, and stop using this flag
[DEPRECATED] The `--without` flag is deprecated because it relies on being remembered across bundler invocations, which bundler will no longer do in future versions. Instead please use `bun
dle config set --local without 'test development'`, and stop using this flag
```
* * *
```plaintext
Post-install message from i18n:
HEADS UP! i18n 1.1 changed fallbacks to exclude default locale.
But that may break your application.
If you are upgrading your Rails application from an older version of Rails:
Please check your Rails app for 'config.i18n.fallbacks = true'.
If you're using I18n (>= 1.1.0) and Rails (< 5.2.2), this should be
'config.i18n.fallbacks = [I18n.default_locale]'.
If not, fallbacks will be broken in your app by I18n 1.1.x.
If you are starting a NEW Rails application, you can ignore this notice.
For more info see:
https://github.com/svenfuchs/i18n/releases/tag/v1.1.0
```
---
### Author:  [@ggurbet](https://meta.discourse.org/u/ggurbet)
#### Post date: [January 7, 2021, 10:52am UTC](https://meta.discourse.org/t/400-bad-request-error-after-upgrading/175277/2 "2021-01-07T10:52:20Z")
Just an update; the problem was fixed by modifying the http headers used when forwarding over reverse proxy (the English terms could be different, sorry if this sentence is confusing).
---
### Author:  [@system](https://meta.discourse.org/u/system)
#### Post date: [February 6, 2021, 10:52am UTC](https://meta.discourse.org/t/400-bad-request-error-after-upgrading/175277/3 "2021-02-06T10:52:39Z")
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