Sex complications

Okayy so has anyone ever had problems with their partners not being able to put their penis inside you well your bent over or you’re trying to do reverse cowgirl??? I’ve never really had this problem with anyone… well anyways we were having sex and we wanted to do doggystyle but the problem was he couldn’t get it in he had the hardest time trying to put it in which was kinda frustrating because I wasn’t really into it anymore and that sucked cause we were having a lot of fun until that I just wanna know if anyone else had this problem and what we’re more easier positions for you guys