apple id locked but recovery says id not valid or unsupported

I tried to create my son an apple id with a gmail account however when I tried to verify the account the code (even though entered correctly) failed. This verification failure happened again and then worked on the third time after being resent by email.

We then tried to get the gmail app on his phone and the Apple id and password failed and has now locked us out.

We tried the recovery on our pc however when we enter the Apple id it says "This Apple id is either not valid or not supported"

Can anyone please advise us on a fix for this?

Thank you