Secondary Infertility?!?!?!

Is it possible to have infertility after two children and the last being a c-section. With my children this far every time we I have inseminated we have gotten pregnant, my wife and I have two beautiful children from at home insemination, I have also had one miscarriage. However after my c-section with my son two years ago I seem to be having problems getting pregnant. We’ve used all the same technique that have previous used and the same donor from the last two pregnancy’s (one successful birth one miscarriage) I guess my question is could my sons c-section be what’s causing my issue or do I need to worry about another issue. Thanks for any advice!