How to create an ERC-721 NFT Smart Contract on Polygon and deploy it on OpenSea

Heyo, thanks for the great tutorial! The instructions are very clear and easy to follow. I've used this video to create a few collections already. I really appreciate you sharing your knowledge and taking the time to make that video.

So far everything works OK, only I'm unable to finalize any sales on OpenSea. I can list items for sale and transfer them between wallets, but I'm not able to actually complete a purchase for some reason. The transaction stops with no error messages or anything. It's weird because the web application displays and lists them just fine.

I checked the discord channels but only found 1 other person who encountered this problem and I didn't find any solutions in the replies. I looked into the issue myself but was unable to solve the problem. I'm pretty sure SaleIsActive is set to true, but it might have something to do with the isApprovedForAll or the supportsInterface functions. I'll continue looking into it on my own but I'm somewhat new to smart contracts and NFTs. Any way please let me know if you have any suggestions. Thanks in advance!