So after we went from MyBB to phpBB then back to MyBB my users cannot log in. If they request a reset through email, they'll either not get it at all, or they will and the verification code in the email will be blank. Even if I change their password through the Admin page they still can't log in. Also I don't know if this is related but I can't stay logged into the admin control panel, after a couple minutes, I'm logged out and told to log in again.
The not staying logged in is probably a cookies issue. The rest is probably settings, which you can't fix if you can't stay logged in. Also make sure you installed the loginconvert plugin as directed by the MyBB Merge System so that their passwords will automatically convert.
Well, I stay logged into the forum but get randomly signed out of the ACP. I can change stuff it's just that it gets annoying to have to log back in again in a couple minutes. I do have the loginconvert plugin enabled but that isn't doing anything in terms of my users being able to login.
OK, a dev/support team member will need to take over from here then as that is more of an issue that I had hoped from your original post
Sorry I couldn't be more help.
URL?? Blank random strings was an issue in 1.4.12 but is fine in 1.4.13.