Just tried this for my husband (we do not file jointly) and it worked! For reference, he owed in 2018 (has not filed in 2019) and we were using the information from his 2018 transcript directly from the IRS but it was still saying it didn't match. We entered AGI "0" and his exact amount owed and it worked. Also, in order to gain access to the portal at all we had to enter our address in ALL CAPS.
Thanks!
