If the needle doesn't insert all the way, I wonder if your last needle broke high up on the shaft and is still in there. I actually had that happen to me on my longarm. I had no idea the needle shaft (the end opposite of the eye) was broken until I went to do a routine replacement of the needle and the new one wouldn't go in all the way. The broken shaft from the old needle was still up in there. I am fortunate that there is a small slit in the side of my needle bar where the needle inserts. I was able to slide a pin in to get the rest of the needle's shaft out.
Since it happened to me I have found out it has happened to others as well, so not entirely uncommon.