1 of 2 likely scenarios:
1. Wrong bleed configuration selected in FMS, resulting in Vspeeds and N1 data dropping out; or
2. Turned pitot heats on too early and cooked the probes, resulting in Vspeed and N1 data dropping out. Can't do anything about it until they have cooled down<40 degrees.
Old trap for newbies. But on the upside they didn't takeoff. Wouldn't be the first operator I know to just blast off.