Unable to record my voice

Hello, the tick mark in the stereo mix is not going , in the recording control , similarly , unable to put a tick mark in the microphone as the tick mark is not going in the stereo mix . Due to this , the person on the other side is unable to hear my voice, although I can hear the other person talking. What should i do to make my voice heard by the other person with whom i am havinga voice call on skype.