What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

IMAP sensor error



The IMAP sensor has a problem. When trying to log in, the following response is returned by the server:

Command requires 2 parameters

I've discovered the problem is because of the password. It needs to be surrounded by quotes (because it contains special characters), which the sensor is not doing. I tested this by using the same email address and password that PRTG is trying to use, without quotes, and got the same error message. I then attempted the login and surrounded the password with quotes, and it worked.

error imap password

Created on Dec 9, 2018 3:14:07 PM

2 Replies



Well - I am not from the PRTG/Paessler support - but I can tell you out of experience that especially IMAP and other mail related services might act differently - interpret the official RFCs differently - even thought just slightly.

E.g. Lotus Notes / Domino servers are pretty harsh - some Linux based IMAP servers are a bit - interesting as well.. and of course some Windows solutions as well...

It could be it is because your password has some very special character that might not translate well in the terminal emulation - or just because the IMAP server is a bit shaky.

The great thing is you found a nice work-around for it - I like it! Still - I don't think the sensor itself has an issue - I personally wouldn't want Paessler to send the text-quotes by default - I rather control it myself as you did :-)

Really thank you for sharing this! I will definitive keep it in mind - it would be nice to know what software is used on the server - if you do - cause this could actually help a lot as well!


Florian Rossmark


Created on Dec 10, 2018 2:51:45 PM



"IMAP and other mail related services might act differently"

That's a very good point. And I agree about not wanting the quotes if they aren't supposed to be there.

To be clear, I didn't find a workaround, it still gives the error. I just used telnet to test what was happening. I didn't see any way of being able to change the sensor. My only solution is to change the password.

I'll let the developer of the IMAP server know what's happening.

Created on Dec 16, 2018 1:31:43 PM

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.