When I moved a couple of years ago I started banking with Fidelity which has 17-digit account numbers. Using those for ACH with ConEd resulted in them failing t

When I moved a couple of years ago I started banking with Fidelity which has 17-digit account numbers. Using those for ACH with ConEd resulted in them failing to bill me at the end of the month. I thought it was a typo and put the ACH numbers in again, only to fail and get disconnected and flagged at the end of next month plus some late fees. The whole problem was that the account number was too long. No error messages anywhere. Fidelity also has a 13-digit account number version that I've been using ever since. What a mess.