To give yourself a good chance to figure this problem out you need to think of everything that is occurring, what is around you, what is different, what has changed? It is very important that if you change something change only 1 at a time and give it a good test. Try and keep the scenario as close as possible to the exact same things each time.
For others to give you advice you need to give very accurate and specific information.
Have you read the manuals for the product you are using. A lot of the time a issue like this is a very simple, small item that is being over looked because it is something that you always have done or it seems like it wouldn't matter.
And be willing to admit that it was something very simple to over look. We have almost all do it or will do it. It happens.
1st - What are the symptoms that you are having?
2nd - What have you tried?
3rd - what do you think it might be?
PS, I fly with my cell phone and about 10+ others within 20-50ft. More than likely not. I have a DX8 and 4 different receivers.