Ok, fixed it.
npm i [email protected] ./nodebb upgradeBut i don't know why!?!?!?
I wanted restart nodebb coz can't login (always error about credentials) and I got new error in command line:
node[email protected]:~$ ./nodebb restart
-bash: ./nodebb: Is a directory
I suspect that these 2 problems are somehow connected. The forum started normally with the usual command ./nodebb start
After that, I swapped the database with a local copy and everything seemed to work fine. I logged in as admin and set up the admin panel, and today I found that I can not log into the forum in another browser.