BillB wrote:
Is this because the frequency for that receiver might be not be working properly or getting interference? The other strobe worked fine on the same frequency.
It would not likely be due to a bad receiver. There is always a possibility of interference when using radio remotes. There is also the possibility of shielding and attenuation. Interference is fairly rare, but switching frequencies should dial you out of any problems.
The red outline indicates a "cannot comply" message. This means the Commander is telling the receiver to do something it cannot do (like take power above maximum or below minimum), or there is a communications error, like the receiver has no power, out of range, etc. This is a good trouble shooting step in identifying the problem. When this outline appears, it is typically when power to a channel is raised or lowered (again, do not try to raise above minimum or lower below maximum).