Am 23.09.20 um 15:29 schrieb nikos:
For some reason none of hotmail or outlook users don't receive any of our newsletter. Finally all of them auto unsubscribe.
The following is an error received form protection.outlook.com:
Remote Server returned '550 5.6.0 CAT.InvalidContent.Exception: ExchangeDataException, Decoding of header Subject failed+ADs- raw value: +AFs-Ps+AF0- +AD0-?iso8859-7?b?wer98fnz5yDF8OX05enh6t7yIOXq5N7r+-fPn8iDz9Oft?+AD0-; cannot handle content of message
That happened since September 10th this year. Before, all received without problem.
Seems you have an encoding problem in your subject fields. I assume you add something which isn't in a character set matching your List settings for default language. Therefore mailman doesn't encode it properly and sends 8-bit characters in the subject. Specifically the starting: +AFs-Ps+AF0-+AD0-
Kind regards, Christian Mack