Hello, and welcome from Michigan!
I don't have that particular machine, but can you tell me if it is skipping and breaking thread or skipping on the top thread or the bottom thread? My DD has a different Janome, and we had trouble with it NOT catching in the bobbin area correctly. There is a small hook that the thread was going over instead of thru and it caused her machine to skip too. We didn't notice the problem until we looked at it thru the back side, so can you re-thread the bobbin and then be sure it is catching right underneath that hook?