SharePoint Backup Failed

Object SharePoint_Config failed in event OnBackup. For more information, see the spbackup.log or sprestore.log file located in the backup directory.
SqlException: Cannot open backup device ….. Operating system error 5(Access is denied.).
BACKUP DATABASE is terminating abnormally.

(Between the word “device” and “Operating” was the path to my backup folder and the actual backup file. I left those out of the message above so that those searching for the error message can find it).

Every time I set up SharePoint backup on a new SharePoint server, I always create a backup folder and share it, then give permissions to the SharePoint account that is used to run the backup from Central Admin, but I always forget one thing. So just in case you forgot it too, or for next time I forget it, here it is: The SQL Server service account must also have read/write control permissions to the backup share.  Remember, it’s also a SQL database backup, so the SQL Server service account is trying to write to this folder.  For more information, check out this Technet article.