i'm not sure if this reported or not (i'm not that kind of guy who reads every single notification)
Game Review Problem

How is this an inaccuracy? does it not SEE the pawn protecting it??
The suggested best move evaluates to almost 3 pawns better; that's why it's an inaccuracy.

I tried to review a position that was a fen, but it said it wasn't working.
Here's a screenshot:
it happened to me a few weeks ago

It doesn't make any sense to run a Game Review on a position. That's what the Analysis tab is for.
sorry i meant like a opening

Also is this not a blunder?? This lets me play checkmate...
Most moves don't get classified as blunders/inaccuracies/mistakes if the overall evaluation of the game isn't really impacted. Regardless of what was played, black is lost so any move is as good as any other, from a classifications standpoint.

It doesn't make any sense to run a Game Review on a position. That's what the Analysis tab is for.
sorry i meant like a opening
Did you have all the moves of the opening or only the position? It's not clear from your image what it could be. If all the moves were there, can you either link to the PGN or provide exactly what you were trying?
I tried to review a position that was a fen, but it said it wasn't working.
Here's a screenshot: