DPM 2016 stopped seeing Exchange 2016 databases

Question

Good afternoon.
I have SC DPM 2016 (version 5.0.158.0) and two Exchange 2016 mail servers.
Everything is fine on server A, but on server B today I was unable to add new mailbases in the DPM snap-in.

• check vss writers - OK
• DPM agent communication with DPM server - OK
• backup of previously added databases from server B - OK
• backup shared folders and files from server B - OK

Here's the informational message that comes up when I click the Refresh Data Sources button:
"DPM was unable to enumerate the Microsoft Eschange Server application component... on the protected computer (ID: 964)"

Thanks in advance!