1. c6's sperm. is it ok, no. motility, normal form?
2. woman's problem, uterus, tube, ovary, is it all ok?
3. time, do do during ovulation day is just 20%. if you're not young, success rate is even lower.
if you try over 1 year, you may see dr. asap and seek for advice.
before that, you can have simple check up with c6 say ultrasound of your uterus and sperm test.