When attempting to log in to Redtail Webmail, a user may see an alert that says "A network service error has occurred". This, in most cases, is a result of hitting the maximum number of failed login attempts within a specific period of time. This is a security feature to help protect your mailbox and the data within it from brute force attacks. The denial-of-service filter (DoSFilter) limits exposure to requests flooding over HTTP/HTTPS connections like webmail sessions. The DoSFilter throttles mail clients and browsers sending a large number of requests over a short period of time.
When this message is received, the IP address from which you are attempting to access webmail has been suspended due to failed logins. The IP will be reinstated after a suspension time of five minutes. If you receive the message when attempting to log in, wait five minutes and you should be able to log in successfully. If you still can not, it is generally due to a mobile device attempting to log in after a recent password change. It is suggested that you check all mobile devices that you may have your account set up on to ensure the password is entered correctly.
One way to avoid this error message is by setting up Two-Factor Authentication (2FA) for your email address. Instructions for this setup can be found here.