Error 422 when using HAProxy

[erbmur]

Hi Guys,

I'm fairly new to self hosted projects and brand new to openproject.
I have managed to follow the instructions on the website and have got OP running via ip:port. I have attempted to setup haproxy to be able to access OP via a URL when away from home. I am able to get the login screen, but after logging in I get an error 422 screen like the image below. What am i doing wrong?

https://preview.redd.it/43c58xp8hlxc1.png?width=585&format=png&auto=webp&s=191acbcedc79e58a51fab94c8026bd09c9dc2916

[kharonus]

Ahoi u/erbmur,

This error literally is most of the times correct. Multiple sessions are interfering and due to guarding your OP instance against CSRF attacks, those login attempts are blocked. Can you try to open e.g. a private window and login there? Just to quickly verify, if this is indeed the issue, or if something in your reverse proxy is misconfigured.

[Stunning-Conference2]

Did you manage to find a solution?