How to resolve failed database backup in SQL Server

Backup database failure may be caused by the following reasons:

1. Not enough disk space: Check if the disk where the backup directory is located has enough space. If not, you can clean up the disk or change the backup directory.
2. Authorization issue: Ensure that the current user has sufficient permissions to perform the backup operation, and consider using an account with administrator privileges for the backup.
3. Database status: If the database is running or in recovery mode, the backup operation may fail. It is advisable to try backing up when the database is not busy.
4. If the database is damaged, the backup operation may fail. Try repairing the database before attempting the backup operation.
5. Backup command error: Verify that the backup command is correct, including the backup path, file name, and other parameters.

If none of the above methods work, you can try looking at the SQL Server error log to retrieve more detailed error information and find a solution.