This error usually occurs if one of the services required for windows backup to work is disabled or not started.
To check for the services, click on start, in the start search bar type services and then press enter.
Please check that the following services are enabled:
"Remote Procedure Call" (RPCSS) should be enabled, Automatic.
"COM+ Event System" (EventSystem) should be enabled, Manual.
"System Event Notification Service" (SENS) should be enabled, Automatic.
"Volume Shadow Copy" (VSS) should be enabled, Manual.
"Microsoft Software Shadow Copy Provider" (SWPRV) should be enabled, manual.
"Block Level Backup Engine Service" should be enabled, manual
Once you make any changes according to the specifications listed above, you can try a backup and check if that resolves the issue