Temporarily blacklisted IP address

I'm getting the following from Outlook 2013 when I try to access my comcast.net email accounts.

"Microsoft Outlook:  Your IMAP server wants to alert you to the following: Temporarily blacklisted IP address - try again later"

Can't retrieve emails.

This error does not occur when using a different ISP.

mxtoolbox.com shows my IP address being on the following blacklist: UCEPROTECTL3

Can anyone help?

Regards,

Brent