Looks like the IMEI number you entered doesn’t match an AT&T device... NO HELP so far from ATT

iPhone 6 Plus... fully paid off. Not under contract. Called and spoke to a very nice rep, who put in a ticket for me... 

"Thank you for contacting AT&T Customer Care about unlocking your AT&T Mobile device:
CASE: [edited for privacy – please do not post personal information]
Thank you for contacting AT&T about unlocking your mobile device.
Unfortunately we are unable to process your request at this time. Please visit us at att.com/deviceunlock to submit a request online. "

Umm, don't you think I would have already tried that? No other solution offered... Complete lack of customer service so far.