External Compass No telemetry when connected

Hi guys I’m having a problem with the external compass.I connected it to the I2C port but the telemetry wont work. I tried with udp and 3dr telemetry nothing happens when external compass is connected in the I2C. I have enabled the external compass in the MP telemetry still doesn’t work.

Could you please provide more details about your setup? What external compass are you trying to connect?