Did you test with a TRRS headset (or earbuds with mic)?
If that works, measure the resistance (to GND) on the MIC pin of that headset.
Not all phones or tablets have a MIC IN (my good old Nexus 7 didn’t have it !). Check the manual if it is mentioned.
And check if you used the correct pinout (I’m sure you did all that 
For once … Apple is RIGHT , Android is LEFT … in the picture I mean, haha.
And just asking ; you didn’t put the capacitor at the phone side , did you ?
PS : good news, I’ll be doing a few summits next week, finally !
73,
Luc ON7DQ