When my father attempts to sign in to his gmail, the 1st time he types his password it says it's incorrect when it's not (he has the 'Show password' box checked to make sure). The 2nd time he enters it, however, it works, but then sends a code to his phone which he has to enter to confirm it's really him. He finds this annoying and has asked me to look for a solution. I've searched online but haven't found anything as yet.
This problem started when I signed him out of his gmail by mistake a while ago and then got his password wrong at least once before successfully signing back in (I think we may have had to confirm using the code from his phone to do this then as well).