Third-party errors are generated when trying to link a bank account. tastytrade does not accept third-party funding of any kind. For ACH relationships, this means that the name on the bank account must match the name on the tastytrade account exactly. For example, you could receive a "third-party" error if your bank account includes a middle initial or suffix that is not listed on your tastytrade account, or vice-versa.
If you receive a "third-party" error, please email our banking team a copy of a recent bank account statement from the bank account you are attempting to link. Send to banking@tastytrade.com. Feel free to blank out any sensitive information, such as statement totals and account activity. The only information we will need visible is the name on the account, the last four digits of the bank account number, and the date the statement was issued/printed. Once we can verify the name on the bank account, we will be able to manually approve the ACH relationship on our end.