Backup server is not available. Snapshot data is incomplete (&1: &2)

What causes this issue?

An error occurred while getting the information about the existing
snapshots. The information could not therefore be read correctly. For
this reason, the display of the snapshots is incomplete. This means that
snapshots could exist even though they have not been categorized as
existing.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Refresh the display using the corresponding button. If the refresh does
not work, wait a moment and try again. If the problem still exists,
contact SAP support. When you do so, specify the following information:
&SYST-MSGV1&:&SYST-MSGV2&.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.