Hi 

Can you check the pop internal connection settings on that server.

get-popsettings  |FL

Hi,
As suggested above can you uninstall/Disbale AV and try?
Please check this URL as well. There are few fixes
https://social.technet.microsoft.com/Forums/exchange/en-US/5f1a2cee-19ad-43e6-b281-bb7f094d8c09/pop-works-via-localhost-but-not-from-other-networked-machines?forum=exchangesvrc

I did Install exchange 2013 Cluster DAG, and system work fine now

The problem is very strange , the POP and IMAP work fine on exchange master, telnet port 110 to exchange 2 as below:

But the POP3 and IMAP on exchange slave not working, telnet on port 110 exchange 1

All configuration on exchange 1 and 2 are the same

When i reboot exchange master, all the POP and IMAP client not working

Anyone can help me ?

• Edited by huynhtrongnhatminh Thursday, March 12, 2015 4:55 AM

The link https://social.technet.microsoft.com/Forums/exchange/en-US/5f1a2cee-19ad-43e6-b281-bb7f094d8c09/pop-works-via-localhost-but-not-from-other-networked-machines?forum=exchangesvrclients

is working for me