Sqlbackupandftp the server principal "NT Authority\System" is not able to access the database "XXXX"

An error was encountered while backing up the database using SQLBACKUPANDFTP in Windows Server 2012:

Error:the server principal "NT Authority\System" is not able to access the database "XXXX" under the current security con Text. BACKUP DATABASE is terminating abnormally.

Ways to resolve this error:

Select the "Advanced Backup Schedule" button in the Sqlbackupandftp tool and set the user to perform the schedule job in the "Advanced Backup Schedule" window, as shown below, You can set up your domain account (the sysadmin role) as the user performing the schedule job or any other account that has permissions.

For official information, please refer to around:the server principal "NT Authority\System" are not able to access the database "Database-name" Unde R the current security context

Open the scheduled job with SQLBACKUPANDFTP software and click to "Advanced Backup Schedule" button. At opened ' Advanced Backup Schedule ' window you can enter user name to execute the scheduled job in "Run scheduled job as" field or just click on ' Set as current User/your personal account ' to use Your current Windows account. Remember to save the job to apply new schedule options. Sqlbackupandftp'll ask you to enter your password when you save the job.

References:

http://sqlbackupandftp.com/blog/hot-around-server-principal-nt-authoritysystem/

Sqlbackupandftp the server principal "NT Authority\System" is not able to access the database "XXXX"