During the backup you can get the following error message:
[SRV:8007#1326] Authorization failed. Computer name: <computer name>. Username: <user name>. Domain: <domain> > The user name or password is incorrect Computer name: <computer name>
That error message is generated by SQL Server and cannot be resolved from our side.
The obvious cause is that the User Name or/and Password is specified incorrectly. Also, the issue can be related to administrative security settings.
How to fix
First of all please make sure you have specified the correct User Name (with a domain name, if it used) or/and Password. For a domain user, full domain User Name should be specified. If the User Name or/and Password is correct and the error message is still present then please check the administrative security settings. In the case that everything is specified properly and all settings are checked then please test if you are able to connect to your SQL Server via SQL Server Management Studio.