Failed to schedule or execute database operation '%1!s!' on database '%2!s!' (Database ID: %3!s!) in availability group '%4!s!' ...

Failed to schedule or execute database operation '%1!s!' on database '%2!s!' (Database ID: %3!s!) in availability group '%4!s!' (SQL OS error: %5!s!).  The instance of SQL Server may have insufficient resources to carry out the database operation. If the problem persists, you might need to restart the server instance.