Setting up a POP3 access on Exchange SBS 2003 server (exchange Service pack 1) for mobile phone access. Original phone worked fine and started downloading mail, but second phone would not authenticate - then first phone also failed to authenticate. Tested from an internal Outlook POP3 account with same problem. Checked all user names and passwords.
Set POP3 logging to Max and found the error
Authentication attempt from (IP address) to (user e-mail address) has failed with error 0x426
Have restarted all services and rebooted server but cannot solve this problem.