Wrong password error (out of nowhere)

Hi. We are suddenly getting a password error for all our physical phones even though the password hasn’t been changed.

Nothing has changed configuration wise.

[Mar 21 08:58:59] NOTICE[25960]: chan_sip.c:27851 handle_request_register: Registration from ‘sip:8557@192.168.8.1’ failed for ‘192.168.8.13:5060’ - Wrong password

Is there anyway to check what’s going on here ?
The only thing I can think of Is that It has someone has hacked the accounts or something along those lines.

Issue has been resolved.

It appears configuration changes were pushed to the users.conf by an application we are using that messed up the configuration.