550 5.0.0 Error

Hello... For some time now I have had this error, whereas before it was correct. ------------------------------------------ 235 2.7.0 Authentication successful MAIL FROM: <.......@..........> 250 2.1.0 Ok RCPT TO: <f5exo........> 250 2.1.5 Ok DATA: 354 End data with <CR><LF>.<CR><LF> Array: 18092025_0833.csv --frontier Content-Type: text/csv ; charset="UTF-8" Readed filename: 18092025_0833.csv SD Check Open file: OK NORMAL Message end 550 5.0.0 message does not have exactly one Date field Sending status: 0 Sending code: 250 Sending desc: Sending message error (550 5.0.0 message does not have exactly one Date field ) EMailSender: All structure created! ----------------------------------------------- I don't understand