Application State Capture Fails Status 47

I have Exchange 2013 CU7 running on Windows 2012 R2 with Netbackup 7.5.0.7 client. The VM Host backup server and Master server is 7.5.0.7 running on Win 2008 R2.

I am employing VMWare backups for Exchange and have installed the Symantic VSS component.

I've noticed that the Application State Capture job is failing with host unreachable.

How can I diagnose / resolve the problem as I fear that I am unable to restore Exchange databases from my backups.

Thank you in advance for any assistance and comments.