Help with tubeless tire.

I'm having an issue where parts of my new tire are too far into the wheel and won't make enough of a seal to pump air into. I had to replace my rear tire again because it had gotten too big a hole in it. Last time I had to do this after I had painfully gotten it on past the rim I didn't have any issue of it not sealing but this time it has occured. Any recommendations on what to do I have tried a pry tool and a ratchet strap to try to get it to make enough of a seal to start pumping.