Backups randomly failing

Good morning all!

We are running Acronis Backup 11.

We have a rotating series of 10 portable HDDS that get swapped every night for the daily backup .

The backups would randomly error and not run overnight, meaning we had to manually set it off in the morning. To counter this we changed from Full daily backups to G-F-S style backups but the errors keep happening.

We have tried different disks/keeping the same disk in. Rebooting the server. Countless online fixes, but none of them have solved the problem.

Thanks for taking the time to try and help and here is the error log that we often get. Worth noting it sometimes changes and occasionally goes through with no errors!

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ProtectCommand: Failed to execute the command.
Additional info:
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Error code: 41
Module: 307
LineInfo: e6792a5ee190dd9e
Fields: $module : agent_protection_addon_vs
Message: ProtectCommand: Failed to execute the command.
--------------------
Error code: 11
Module: 373
LineInfo: dfd7515541030d07
Fields: $module : staging_command_addon_vs
Message: Failed to resolve the secondary location. Location: 'arl:/CF911C34-40C1-468E-B794-AFE627E467E7/FC4D4894-DB14-4D74-A56E-D8A4FAB5A842'; Archive: 'Archive(1)'.
--------------------
Error code: 507
Module: 64
LineInfo: a1d3981537c6874e
Fields: IsReturnCode : 1, $module : disk_bundle_vs
Message: Failed to open the backup archive by the ID.
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Error code: 507
Module: 64
LineInfo: a1d3981537c6874e
Fields: id : Archive(1)_2013_01_22_23_01_11_020D.TIB, $module : disk_bundle_vs
Message: Failed to open the backup archive by the ID.
--------------------
Error code: 1
Module: 64
LineInfo: 98130db273d2480
Fields: $module : disk_bundle_vs
Message: The archive is invalid or its type is unsupported.
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Error code: 9
Module: 64
LineInfo: 95962d9a14426d2d
Fields: $module : disk_bundle_vs
Message: Failed to find the backup.
--------------------
Error code: 9
Module: 64
LineInfo: 95962d9a14426d2d
Fields: $module : disk_bundle_vs
Message: Failed to find the backup.
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