Any suggestions for better text to put for this error message so the next person will be less likely to be confused?

It's trying to tell them their clock is wrong and they need to correct it.

It's relying on 3 time sources:
1) the system clock
2) the other nodes, if within an hour of the system clock
if those disagree, then
3) the user (asking the user to fix the system clock)

I've thought about NTP, but this is more secure.