I had trouble getting my Wells Fargo account to connect initially would give a generic error message saying to contact customer support. The problem was that Well Fargo didn’t like the cell phone number on file (it was Google Voice number which some don’t trust to send OTP).
This was very confusing because I was able to login on the Wells Fargo website directly without any issues and the error message was very generic. Apparently when connecting your account to Wells Fargo account to Tiller; Wells Fargo require’s two factor authentication (even if you don’t need it when loggin via webpage).
So TLR: check that your cell phone on your bank profile is correct, if you having trouble linking an account.