Dear All,
We are facing problem in connecting our MS Exchange 2003 POP3 services. The problem occurs intermitently, we are able to telnet the servers

telnet servername 110 and receive a response from the server. However, the users are unable to connect the PO3 services.There is one Front End server and two backend servers of Exchange 2003.
TO solve the issue we have to restart IIS services and then the users are able to connect to the POp3 services.
The Error in outlook is
Task POP3 - receiving reported error (0x800CCC0F) the connection to the server was inturrupted.
Please suggest.

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I suggest you follow this document to troubleshoot the issue:
Error messages when you send and receive in Outlook and Outlook Express

http://support.microsoft.com/kb/813514

Thanks,
EvanEvan Liu
TechNet Community Support

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Hi Evan,

Thank you for replying, but the issue is faced by all POP3 clients. And it can only be solved by restarting IIS on the Exchange 2003 Frontend server.
Will there be any settings related to IIS that needs to be looked into ?

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Hi Vikram,
I am suspecting this is because of your App Pool is getting crash & Hung, to troubleshoot that i could just suggest you the way.
a) Enable the POP3 Logging.
b) Check for the events & is it happening on specific time - peak hrs or non peak hrs.
c) Check and Review the POP Logs.
d) Reduced or Limit the no of Connection for IIS (Apps Pool).
Regards,
Ashwini Kumar
Happy to Help.
Know more about Messaging :-)

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Hi Ashwini,


thanks for the update. This issue is hapenning in non peak hours also. i shall check the logging option.
In between can you please help if the following Knowledge base will be of some relevance

http://support.microsoft.com/kb/816896


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I dont think this link which you have share is relevant or have the same symptoms which you are explaining in your first thread.
Regards,
AshwiniKnow more about Messaging :-)

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Hi Ashwini,
Enabling Diagnostic logging for POP3 Protocol helped identifying invalid authentication on the server. We could find as many has 30-40 invalid connections per second on POP3 Protocol generated from one of application server which used pop3 protocol to download
emails. The application was stopped from downloading emails and invalid connections stopped.
We suspect this could have caused the problem. Keeping the issue under observation.
Thanks.

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