creating Recovery Points fail after updating to System Center 2012 R2 UR4 – Connection to VMM lost/refused

Two days ago the final release of UR4 for SCDPM 2012 R2 came around. There’s still no deduplication support available but this isn’t the point right now. If you use Uninterrupted Data Protection with Virtual Machine Manager, you may encounter the same error as me:

Description:    DPM was unable to establish a connection with the Virtual Machine Manager (VMM) server.
Server name: 

SCMVMM-01.
Exception Message: Type: System.ServiceModel.EndpointNotFoundException, Message: Could not connect to 

net.tcp://dpm-03.contoso.com:6070/VmmHelperService/TcpEndpoint. The connection attempt lasted for a time span of 

00:00:05.0829204. TCP error code 10061: No connection could be made because the target machine actively refused it 

[IPv4/IPv6 Adress]:6070.  (ID 33400)

For whatever reason most of the DPM Servers I already updated forgot what they have been doing for months.

Re-establishing the connection helped.

Set-DPMGlobalProperty -DpmServerName  <DPMServerName> -KnownVMMServers <VMMServerName>