Verify that there is a connection to the SQL Server instance where the database being backed up/restored was created.
Verify that the client is registered to the backup system.
Verify that SQL Server is running on your machine.
Confirm that the database is being restored to the same device type that was used to backup the database.
Confirm that the client’s hosts file has been updated to include the backup system name and IP Address.
Delete the current database schedule association and reassign the schedule. Modifications to the backup schedule do not affect associations that were created prior to the modification.
If this state occurs, restore the database to the latest possible time and perform the restore again. This could have occurred due to a backup and restore of another database taking place at the same time.
If the SQL Server Agent is being used in conjunction with another SQL Server maintenance plan, the transaction logs get out of sequence. The database is then seen in loading state. This database should be removed and a full restore along with any differentials must be performed. This restores the transaction log chain.