If you think your username/password login is not working, and that you just have to keep resetting your password for access, the reason could be very simple:
1) Check capitalization of your password - it won't work with the wrong capitalization!
2) Check your username - not just for spelling, but for spacing too! If you are allowing spacing in your username, make sure you have the right spacing. Using 1 or 2 spaces in your username, for example, makes a difference!