What might cause this IMAP client error - "'Unexpected: Non-last response line..."

[edwinyzh]

The error happens during the execution of TidImap4.UIDRetrievePeek, any hint as to trace the source of the issue?

And here is the full error message:
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Debugger Exception Notification
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Project program1.exe raised exception class EIdReplyIMAP4Error with message 'Unexpected: Non-last response line (i.e. a data line) did not start with a *, offending line: nthalten. Sollten Sie diese E-Mail irrt=C3=BCml='.
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Thanks.

[rlebeau]

The error happens during the execution of TidImap4.UIDRetrievePeek, any hint as to trace the source of the issue?

Not without seeing the complete IMAP response that was received from the peek command. But, the error basically means that the response contained at least 1 line of text that did not start with a leading '*' character, and that line was not the last line in the response. UIDRetrievePeek() sends a FETCH command, and every line in the response, except the last, should begin with "* # FETCH ..." (where '#' is an email message number), and the last line contains the final status code for the response (OK, NO, BAD).

[edwinyzh]

Thank you @rlebeau