If the FM is 900 then you have probably been trolled...
When an FM is rated 900...

Do you mean for online games? If so, then the answer is simple: you laugh at them. Either because he/she is so bad and still somehow managed to get the title, or (more likely) the only way he/she can feel better about their skills is to deliberately lose a bunch of games to weaker players. Both are very unbecoming of any titled player.

Bad internet connection. Just saying.
By online games, I don't mean Live Chess games. I mean 24 hours per move kinds of games or longer. So unless the person in question has the most unpredictable and unreliable internet ever that goes off for days at a time, I'm sure it doesn't affect those kinds of games.

Or maybe it was some clown whose chess.com name is FM whatever. If the FM is in red, then it's real; otherwise it means nothing. Lot of that going on here, mostly kids.
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