@MoJo Ah yeah it looks like you've run into this bug: https://github.com/NodeBB/NodeBB/issues/8515

You'll need to cherry-pick the referenced commit to fix it in your install.

joolswills created this issue in NodeBB/NodeBB closed NodeBB redirects to / rather than subfolder /forum on login #8515

@a_5mith said:

sudo apt-get install -y redis-server

thanks for you all your help @a_5mith

It was a problem installing Redis, nothing to do with NodeBB. I forgot to install tcl8.5 for a propper redis installation in debian.

I hope this help for future related problem, you can see how proper install redis following these steps: