unable to add exchange 2013 sp1 to DAG

I have a 4 member Exchange 2013 sp1 DAG. Its running on Windows 2012 R2. When I tried to add a new member, it get this error. The new member is running windows 2008 r2, instead of 2012 r2. Does Exchange 2013 sp1 DAG support this config?

A server-side database availability group administrative operation failed. Error The operation failed. CreateCluster errors may result from incorrectly configured static addresses. Error: An error occurred while attempting a cluster operation. Error: Cluster API failed: "AddClusterNode() (MaxPercentage=100) failed with 0x5b4. Error: This operation returned because the timeout period expired".