It is indeed an SOS which is a pretty rare occurrence. A reboot will always recover your Tablo from this.
Our servers were affected by a short outage during regular overnight maintenance hours. In general this shouldn’t affect your Tablo much more than missing guide data updates and a bit of database cleanup.
However, we did find a small bug that will cause a subset of Tablo DVRs to enter this protective SOS mode after many unsuccessful attempts to reach our servers in a row.
This will be corrected in the next firmware update and our servers generally have a 99.9% uptime so you hopefully shouldn’t see this again.