Description
Error occured during Backup procedure
System.Data.SqlClient.SqlException (0x80131904): Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
Cause
If you have an old backup (i.e. taken from a UCX Suite version earlier than 2017.Winter.1), and the original database was several GB in size (the threshold is approximately 5 GB) you won't be able to restore it.
Solution
Update the old UCX Suite to a newer version (> 2017.Winter.1) and take a new backup.
Check also if the database used by the old UCX Suite version is the same type (Express or Standard) like the new UC Suite server.