Interference using maxon pm100 2 way radio

Question

We have used this radio system for 8 years for our taxis. For the last 4 days we have had a great deal of interference. So much so that on many occasions all we hear is a crackling noise and cannot hear the operator speak. There is an orange light coming on which was previously green when the operator spoke and red when the driver spoke. Can you please help us solve the problem.Thank you