&1 is not accessible in the storage system; can therefore not be deleted

What causes this issue?

The data archiving process for this archiving object is configured so
that the archive files created are first stored in a connected storage
system then processed by the delete program. After storage, a copy of
each archive file remains in the file system. These are not removed
until the delete program has completed successfully.
In this case, the file in the storage system is not accessible.

System Response

For security reasons, the copy of the archive file has not been removed
from the file system.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.