It is a weird POP3 connection behaviour for outlook connectivity

We have 2 x MBX in DAG and 2 x CAS servers in HA load balancing

POP3 enabled users when configured in outlook at certain times get password prompt and this sometimes continues upto 30 minutes , outlook connection is set to POP3 port 995 to use SSl and smtp port 587 to use TLS on same external url

at sametime ping and telnet request get connected but outlook does not

Are you doing any SSL offloading?

Have you tried connecting directly to one of the CAS servers, bypassing load balancing, to see if that might be the

yes we have tried to connect directly to either of the CAS servers but same password prompt issue

is this related to receive connector maxinboundconnectionpersource as the client connect to the servers through a P2P line, so the connection IP is same for all the users

OR is it related to POP settings

Hi FNS,

What's the version of the exchange 2013?

I found a article which may give you some hints :

Exchange 2013: Pop/Imap clients unable to Authenticate

Please note: Since the website is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information. And the changes made in the above blog is not supported officially by Microsoft.

Best regards,

Hi Niko,

the post applies to CU1 but we are having CU3 installed

and according to the post we have enabled the POP logs, the logs for failing users are as below

2014-11-17T05:03:57.654Z,00000000000404E0,2,172.30.5.61:995,172.30.5.230:55057,user@domain.com,1,41,5,user,user@domain.com,R=ok
2014-11-17T05:03:57.778Z,00000000000404E0,3,172.30.5.61:995,172.30.5.230:55057,user@domain.com,93,10,56,pass,*****,"R=""-ERR Logon failure: unknown user name or bad password."";Msg=LogonFailed:LogonDenied;ErrMsg=LogonFailed:LogonDenied"
2014-11-17T05:03:57.841Z,00000000000404E0,4,172.30.5.61:995,172.30.5.230:55057,user@domain.com,0,0,0,CloseSession,,

The above logs state that username/password is incorrect but we are able to login to with same password.

Logs when user able to connect
2014-11-17T05:04:40.800Z,00000000000404F2,2,172.30.5.61:995,172.30.5.230:11442,user@domain.com,1,41,5,user,user@domain.com,R=ok
2014-11-17T05:04:41.144Z,00000000000404F2,3,172.30.5.61:995,172.30.5.230:11442,user,326,10,34,pass,*****,"R=ok;Msg=""Proxy:MBX01.domain.local:9955:SSL;ProxySuccess"";ActivityContextData=8506f839-340a-4502-98db-92ea7b001d94"
2014-11-17T05:04:43.368Z,00000000000404F4,0,127.0.0.1:995,127.0.0.1:59883,,50,0,51,OpenSession,,
2014-11-17T05:04:43.368Z,00000000000404F4,1,127.0.0.1:995,127.0.0.1:59883,,0,0,0,CloseSession,,

 

Hi 

Got any solution for this?

I also have the same problem.

For the users in the one of the mailbox servers is the problem, others working fine. POP settings are same in bot mailbox servers.

Thanks,

Najeeb

• Proposed as answer by Najeebca VU3NGB 23 hours 3 minutes ago
• Unproposed as answer by Najeebca VU3NGB 23 hours 3 minutes ago

Hi

I have resolved the problem myself.

Two things have to configure.

1.  Insatall a valid certificate in mailbox server and assign this certificate to smtp service..

2. add x509certificatename in popsettings for mailbox server . 

Thanks

Najeeb

• Proposed as answer by Najeebca VU3NGB 23 hours 1 minutes ago

Hi 

Got any solution for this?

I also have the same problem.

For the users in the one of the mailbox servers is the problem, others working fine. POP settings are same in bot mailbox servers.

Thanks,

Najeeb