Recently during an Exchange 2003 to Exchange 2010 migration we were trying to move the mailboxes to Exchange 2010, after repeated tries we kept getting the same error

MapiExceptionNetworkError: Unable to make connection to the server. (hr=0x80004005, ec=2423)


Event Viewer didn’t reveal much about the error message, to troubleshoot further we executed simultaneous WireShark traces on Exchange 2003 and Exchange 2010 servers.

The network traces found that Exchange 2010 server is trying reach out to Exchange 2003 on port 6001.

We went ahead and opened the required port on the firewall, after which mailbox move worked fine.

I would suggest testing with Firewall turned off, Incase Port 6001 doesn’t resolve your issue, to ensure its a network problem.

Feel free to report new issue on our forum

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An automobile enthusiast at heart and computer geek by profession, started my Career with MS in 2005.Left Jobs and started Pledge Technologies (the parent company to Grishbi) back in 2009.We have been providing IT consulting to various Small and Medium businesses across US and UK since then.Our company specialises in Microsoft Server technologies like AD, Exchange, the rest and with numerous Office 365 migrations under our belt, we quite an expert with that too. Whatever we learn in our day to day life, we share it back on Grishbi as a Thank for all the love and support our customers have given us.