I have a Windows 2012 Data Center Server running multiple Virtual Servers. One of these is my Mail server. It is a 2008R2 Virtual server with 2 virtual adapters. 1 for the internal network, 172.*** works ALL the time no problem. One for the External Network, 12.**** works initially for a few minutes then fails with a Yellow ! and will no longer connect to send mail. If I DISABLE the External Virtual adapter in the 2008R2 virtual machine, and re-enable, it will work again for awhile then go back to the failed state.
I removed the virutal adapter....re added with a different nic card in the Host and still same results.
Any Suggestions or help?
Very strange problem.