In the pop3 connector the error "LumiSoft.Net.IO.LineSizeExceededExeption" is shown.
The Solution is also applicable to the error: "error while fetching messages from server, 1 messages with errors"
The error "LumiSoft.Net.IO.LineSizeExceededExeption" happens when mailclients are used, that dont use a mime conform line break.
Expected would be CRLF (CR+LF, '\r\n', 0x0D0A), but the mailclient only uses CR (\r) oder LF (\n).
This results in a corrupt mail, that is stuck in the pop3 connector.
The email in question must be deleted from the mail server.
When email alerts are enabled, the administrator will get a mail with the corresponding SEQ ID for the corrupt mail.
This is usually SEQ ID 1, since it prevents the further processing by the connector.
Download the REDDOXX POP3 Client: Pop3Client.zip.
With the pop3client you may identify the corrupt mail with the Sequence Number, inspect the mail and mark it for deletion.
Upon closing the client, all messages marked for deletion will be deleted on the mailserver.
With other exceptions in the POP3 Connector, the pop3client might be helpful too, as more details to the mail can be shown there.