Is there an error in the draw decision?

There's no stalemate-draw rule here — stalemate doesn't count as a draw.

White either offered draw or let the time run out.

@Deadban said ^

White either offered draw or let the time run out.

No, this is a correspondence game, time is enough.

It says white claimed a draw (well, it didn't say the color but white is the only one who could have done it). Did you really not press the draw button after playing Qf3+?

No, I didnt.
Draw claimed • Insufficient material
this is the reason for draw

@Deadban said ^

White either offered draw or let the time run out.

Draw claimed • Insufficient material -> white click draw and black can't win auto-claimed

@Bishop-Slash said ^

No, I didnt.
Draw claimed • Insufficient material
this is the reason for draw

You may have clicked in draw button

Ok, really a unique draw, without the opponent's agreement

@SergioGlorias said ^

No, I didnt.
Draw claimed • Insufficient material
this is the reason for draw

You may have clicked in draw button

It would be nice when the system shows this draw offer before the game ends with Draw claimed • Insufficient material.
The pgn export shows a different result of the game: [Termination "Insufficient material"].
In my opinion, this should also be checked, as it leads to an inconsistency.