There seems to be a limit to 16 chars for the bugzilla password.

This limit is not displayed:
* when updating the password of an account
* when resetting the password

And worse, when resetting a password, the length is not checked.

So I can go, click on reset my password, enter a 20 chars long password and it goes through, but then I can no longer log-in because the password is truncated but there is nothing mentioning it.

After resetting my password 3 times I finally went for a shorter version which finally allowed me to log-in on the bugzilla, then I tried to update my password via the 'my preferences' page and that's when after trying to put back my long password that I learned there is a limit to 16 chars.