If part of the problem is that you're not breeding them often enough, take a calendar and make a schedule. Long intervals between litters can sometimes make for difficulty conceiving due to the accumulation of fat in the body cavity. At just over a year, this should not be a big problem - YET - unless you overfeed them.
I will be using a calendar going forward. It is too easy to forget what day you did what with whom. I actually started one with the last breeding on the two does. I didn't know about the long intervals making it harder to conceive. I learn something from here everyday. I believe that I was overfeeding them until three months ago. I didn't realize what a huge issue this was until then. They are now all on a measured food amount. Hopefully, it's not too late.
Do the does lift for the buck when he has mounted them? With a little practice you should be able to tell. Watch closely while they breed. Watch too for the buck falling off afterwards -- it usually indicates that he has completed the act. Mark your calendar and put the nest box in on Day 28. Most does kindle around 30-32 days after breeding, but leave the nest box in for another week after that because sometimes they go longer.
I will watch for the lifting on the next try. We have only had the buck fall off once that I can remember. I also read where you should keep them together (if everyone is civil) for about a half hour which might be part of the issue. We were taking the doe out after two mountings ( probably 5 -10 minutes) even though he wasn't falling off either time. It is now too hot here to breed so I will have to wait for cooler temps.
Lots of beginners experience problems of one type or another. Try to address them as they arise. Ignoring them will get you nowhere.
Yes, the maybe next time approach is not working out at all.
Some people start off with great success only to be landed with a major crisis down the road a little. On the whole, I'd rather have my problems at the beginning and then troubleshoot them.
Good luck! :good-luck: