After icloud restore my iPhone is asking for the password to my iPhone is asking for the password to my old, as in not an email, appleid

Back in 2013 (something like that) users had to migrate their appleid, often times not an email address but just a username, to a new appleid which obviously is an email address. I recently had to restore my iphone from an icloud backup and am now being asked for the password to this old username. I've given it my current password but it claims this is not correct.