Common causes and solutions for Webmail login problems:
Don't forget that there is no "www" in front of "webmail.pepperdine.edu". The proper address is "http://webmail.pepperdine.edu" (without quotes).
The University's Webmail server may be experiencing difficulties. If possible, please report this to the University Help Desk at (310) 506-4357. They are usually able to resolve the problem in less than a half-hour. In the meantime, you may attempt to use the backup server: http://webmail2.pepperdine.edu
Your account may be locked out (occurs if you make several bad password attempts in a row): Call the University Help Desk at (310) 506-4357 to request that your account be unlocked. Your account may also unlock itself after some time.