I guess we may not be too different in opinion. I definitely think the OP should NOT try and “diagnose” the issue. It’s not their problem to fix and in the wors

I guess we may not be too different in opinion. I definitely think the OP should NOT try and “diagnose” the issue. It’s not their problem to fix and in the worst case, trying different account numbers as others suggest in this thread may end up with your money in someone else’s account - now you have two problems instead of one. Imagine trying to explain why you took those actions to a non technical peer (maybe a judge). “Well your honor, the luhn check digit algorithm…”