IMAP authentication fails in multiple apps although webmail works

My Comcast email account works normally through Xfinity webmail, and I have verified that my username and password are correct.

However, I cannot authenticate to the account through IMAP.

I have already completed the following troubleshooting:

• Verified Third Party Access Security is enabled.

• Turned Third Party Access Security off and back on.

• Verified the correct Xfinity IMAP settings: imap.comcast.net, port 993, SSL/TLS.

• Tried both Wi-Fi and cellular data.

• Tried Microsoft Outlook for Android.

• Tried the Gmail Android app as a completely separate IMAP client.

• Both apps report that my username/password or credentials are incorrect.

• The identical username and password work successfully in Xfinity webmail.

I previously contacted Xfinity telephone support and was told the problem was that my mailbox was full. I spent several hours deleting email and reduced my mailbox usage to approximately 75%. This made no difference whatsoever. IMAP authentication still fails in both Outlook and Gmail.

Because two independent IMAP clients fail authentication while Xfinity webmail accepts the same credentials, this does not appear to be an Outlook, Gmail, password, or mailbox-storage problem.

I need this escalated to the Advanced Repair/Email team to investigate the server-side IMAP authentication or mailbox provisioning for this Comcast.net mailbox. Please open a repair ticket rather than repeating the standard email-client configuration troubleshooting.