Can't host more than one server with VAC per IP

I run a Windows 2008 dedicated server and I’ve never had this issue until just now: Whenever I try to host more than one server on one IP but different ports, it does not enable VAC on the server, and gives this unique error in server’s console whenever VAC isn’t working:

Failed to load Steam ServiceBOpenService failedServiceStart: failed to startCrea
teBoundSocket: ::bind returned Win32 error [no name available](10022)
cminterface.cpp (821) : Assertion Failed: 0 != m_hConnection
Assert( Assertion Failed: 0 != m_hConnection ):.\cminterface.cpp:821

I believe that error is actually causing this issue because this person had the same issue, and also has that error:
That person also is running Windows 2008 so it’s possible this issue is unique to Windows 2008

Does anyone have any ideas about how to fix this?

I’m not quite sure, but it also may do something to Valve’s servers overloaded to fucks. Ya know, TF2 going F2P caused a quite stress for their servers.

Seems unlikely, since if it was actually the case (VAC overloaded), then why does VAC still work if I host on an unused IP?

Bump. I need help please? I have a limited number of IPs and would not want to be restricted to one server per IP.