Authentication failed because the remote party has closed the transport stream

[HendrikSchinnenburg]

Hi,
since 2 Months we get the error in the title if we connect to office365 pop3 Mailboxes.
We connect using "usessl True"

Dim pop As New Pop3Client
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
pop.Connect(popsvr, popport, useSsl:=True)

Nothing helps, anyone there wh can help to get a stable connection?

Kind regards
Hendrik