Error Code [30:325] A backup operation on AlwaysOn databases fails

A backup operation on AlwaysOn databases fails with Error Code [30:325]

Symptoms

A backup operation that runs on the AlwaysOn databases fails with the following error message on the SQL Server:

Error Code: [30:325] Error encountered during backup. Error:[Microsoft.SqlServer.Management.Common.ExecutionFailureException: Cannot backup from a HADRON secondary because it is not in Synchronizing or Synchronized state. BACKUP LOG is terminating abnormally. An exception occurred while executing a Transact-SQL statement or batch.]

Causes

One or both of the following conditions are causing the backup to fail:

• The secondary replica cannot communicate with the primary replica.
• The primary and the secondary replicas are not in either the Synchronized or the Synchronizing state.

Resolution

For a successful backup of the AlwaysOn databases, verify that the following two conditions are met:

• The secondary replica can communicate with the primary replica.
• The primary and the secondary replicas are in either the Synchronized state or the Synchronizing state.