Windows Mail app fails on Comcast email with VPN turned on

Hi,

I use the Windows Mail app to monitor all email accounts at once. When the VPN is turned on, the mail app fails to receive email for the Comcast.net account. All the mail app says is, "check your settings". Outlook & Gmail have no issues. Occasionally, even with the VPN on, Comcast mail does still make its way through. Why is that I wonder? 

I understand the email provider is just protecting my account from a masked IP address, but I am hoping there is a workaround. Found information regarding different port assignments for IMAP settings to bypass the VPN block. For instance, local port box 443 or 80. Perhaps I am not on the right path. Also found threads regarding Split Tunnel Features, sounds complicated, which Norton may not support yet.

Norton™ 360 with LifeLock™ Select version 22.22.9.11

Windows 10 Pro

Thanks for any assistance.