AOL Mail still exists, but in 2019 they stopped supporting ancient "screen names" and forced users to add phone numbers. Many users ignored this. Now when you log in, AOL says "We need to verify your account via TXT" but the code never arrives.
The string gmailcom yahoocom hotmailcom aolcom is what happens when the period (.) is omitted. The correct domains are: gmailcom yahoocom hotmailcom aolcom txt 2019 fix