Issue pop3 loop

[dvl]

Server operating system version

windows server 2019

Plesk version and microupdate number

Obsidian

"
Recently I've upgraded my server from Plesk 11.5 to the last version 12.5.
Now I've a high POP3/IMAP traffic for a single domain (from 30 to 300 GB monthly).
I'd like to know if is possibile to find the single email (the domain has more 30+ emails) that use improperly the IMAP/POP3 service.
Plesk offer a tool for this?
Alternatively, is there any script/plugin?
Thanks."
I have similar problem but Plesk Obsidian for Windows. What can i do to solve this?

 

[IgorG]

Is it a potential spam message?
Or why did you copy an old post from #1

 

[dvl]

Is it a potential spam message?
Or why did you copy an old post from #1

It's not a spam issue. My customer is complaining that pop3 generating way more traffic as it should be. His usual pop3 traffic is about 10GB and it jumped to 133GB. I copied old post as example and here is one more example of this problem i found on internet:
"
Hi, we have one client who saw a giant increase in bandwidth last week, and it is all showing as traffic from POP3. It's averaging 7+GB/day, where previously it was 40MB/day! Everything else is normal (which is very low).
I found out that the day the traffic spiked the client had setup a new account at Outlook.com and set it to check her domain email using POP3. Previously, she had used an Outlook desktop client on her computer using IMAP. She does have a lot of stored emails with some sizable attachments.
So wondering if the account on Outlook.com could be stuck in some sort of a 'download loop?!?' She still has her email on the server when she checks via desktop Outlook.
She tried to disable the account in Outlook.com, but was not able to login using the email and password she setup. She eventually was able to get support staff to help her, but they just setup a new account using the same info and said that IT WOULD OVERRIDE THE PREVIOUS account (think they were only able to find it using her phone number). So there's some weirdness trying to get to that account she setup.
- Is there anything I can do from the WHM/cPanel side of things to stop this one particular run-away POP3 account without disabling email altogether??
Obviously, would be important not to lose her email in the process.
- Could this be some sort of malicious behavior that would cause such a huge spike in POP3 traffic?
Thanks!"

 

[javcove]

I´m having a similar Issue when users setup their POP account inside hotmail.com, outlook.com or gmail.com. The POP/IMAP traffic goes up by 80%.