MP3 export mix lacks audio from one track[SOLVED]

I am a new user I have Audacity 2.0 and windows 7

I recorded a voice narration with background music. I can hear both voice and music when in Audacity however when I export to MP3 only the music is on this file. I have followed instructions in the tutorial but I cannot seem to correct this help please

Ensure that you are using “File > Export” and not “File > Export Selection”.
If that does not solve the problem please describe precisely step-by-step what you are doing.

Hello Steve,
I have been going to file> export> and saved to MP3, I have also tried saving to >wav microsoft 16

Make sure neither track has the “Mute” button depressed.

Make sure the -…+ gain slider on the voice track (to left of the blue waveform) is not over to left.


thankyou Gale

the voice slider was on the left side .