verb
BAD : First of all I'd like to congratulate you both for your wedding.
GOOD : First of all I'd like to congratulate you both on your wedding.
◆◆◆
congratulate sb on ( doing ) sth : 'The President was among the first to congratulate the crew on the success of their mission.' 'On behalf of the school, I'd like to congratulate the first eleven on getting through to the final.'