My ISP uses Dovecot and I have had an ongoing problem for a while using several email clients.

Sometimes the response to a retr request is mal-formed. The expected response "+OK nnn octets" is not returned. The response looks like it started somewhere in the message headers.

Sometimes a retry can clear the problem but I usually need to delete the first message via a putty session.

The problem, when present, is always on the first message. Never seen it in the middle of a series of messages. This problem has been seen on different machines, different versions of Windows, at home and on the road.

I have wireshark traces showing good and bad sessions....

stat +OK 93 1000437 retr 1 +OK 6946 octets Return-path: .....

retr 1 of blahblah@blah.com designates 2607:f8b0:4001:c03::235 as permitted sender) smtp.mail=blahblah@blah.com; dkim=pass header.i=@blah.com Reply-To: android-developers@googlegroups.com Precedence: list Mailing-list: ......

My ISP has been non-helpful. Any ideas how I can track down the problem?

Thanks Bill