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IMAP sensor: Connection Closed Gracefully



I have a IMAP sensor which has worked without problems until recently. The error output is "Connection Closed Gracefully" and often lasts less than 1s but as far as I can tell, the server is running as usual.

Any ideas?

error-messages imap imap-sensor

Created on Mar 18, 2014 10:21:19 AM

3 Replies




thank you very much for your KB-Post. May I ask, what exactly is the target mail server? Microsoft Exchange? Were there any updates made to the mailserver recently?
Also, is it correct, the sensor shows this error now constantly? Or does it flicker between UP & DOWN with this error message then?

best regards.

Created on Mar 19, 2014 1:10:05 PM by  Torsten Lindner [Paessler Support]



Hello, The target mail server is SmarterMail running on a VM windows 2003 R2. The VM is updated monthly but the SmarterMail service is seldom updated.

It flickers, as you say, between UP and DOWN with this error message, although it hasn't triggered any alarms recently ie the last week. When it triggers, it triggers constantly for anything about 10 min up to an hour at a time and then quits.

Created on Mar 25, 2014 8:33:34 AM



When the sensor is down again for the next time (for a bit longer than a few minutes), please check the logs on the mail-server for any hints on this issue. You can also enable the option "Write sensor result to disk (Filename: "Result of Sensor [ID].txt")", in the Settings of the IMAP Sensor in PRTG, to maybe see the steps before the connection close.

Created on Mar 25, 2014 1:43:06 PM by  Torsten Lindner [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.