When logging into webmail, you may see the following error:
Security Policy Handling Failed.
Please contact the system admin or check the error_log file.
This error means that the password you have set for that email account is too weak and does not match our security policy for password complexity. To resolve this, please login to your cPanel separately, and change your mailbox password in cPanel -> Email -> Email Accounts. This will resolve the issue, because cPanel will ensure that you set a sufficiently complex new password.