B800fs will not allow incoming file transfers

My B800fs is attached to my network via a switch. Up until Monday, everything was working fine. On Monday I tried to copy a file to the B800fs and I get the message saying that there is no available space. Drobo Dashboard tells me that there is 5.69 TB of space available (total space: 21.67TB) on the B800fs. If tried using a Mac and a windows computer and get the same message. If tried using the administrative account and get the same result. I’ve reboot the B800fs, still no change. All lights on the unit are green! It has the latest firmware and I’m using the latest version of Dashboard. I’ve checked the B800fs rights and all looks good. Not sure what else to try. If the B800fs is truly full, why am I not seeing any red lights or indications in Dashboard?