Drobo B1200i - Unable To Connect To Volume via DPM

We’re running Exchange backups to the B1200i using DPM and after attempting to assign a new volume to address some space issues, we lost connectivity to the original volume on the Drobo. DPM starting seeing duplication in Disk assignment and finally spit out an “Unhandled Exception in Managed Code Snap-in” error. Microsoft was able to determine that there are volumes on the Drobo that are reporting unavailable. While other volumes being used by DPM are available. Knowledge base recommended running chkdsk. Failed and did not correct the issue. Please advise.