When a Syslog-ng Store Box (SSB) tries to archive it fails with the following message:
Archiving failed. reason: Failed to create archive directory - mkdir(): Permission denied;
The Syslog-ng Store Box (SSB) IP address needs to be that of the Management IP, not the External IP, if the management interface is being used.
Once the /etc/exports file on the NFS host has been modified with the correct IP the archive should be successful.