Miner and 5 solo units has been running fine for weeks and weeks.
Today the dashboard showed no data. It looked like every unit was offline even though they were still running (fans) normal speed and all had flashing red lights.
I tried stopping and starting, then rebooting everything and finally I loaded a new image on a new micro SD and the miner still won't start.

The node is running fine. Every time I click start on the miner, the fan starts to spin up for about 0.5 second and then goes back to idle mode. I disconned all the standard units but that changed nothing. Checked all the plugs, green led is is on.

To recap: new SD &  all units have red flasking LEDs  but the miner won't start. Node runs fine.

What is my next step?