Cannot set properties of null

Hello everyone, I’m on one of the last parts of " Minting and Selling NFTs Without Paying Gas Fees! NFT Minter Programming Tutorial" and I’m getting an error which I really can’t find a solution to. I have tried many different things but with no success. Can anyone help me? Thank you!
Here is a screen shot of the error and my script.

what is the line that gives that error?

if is the last one, then where is what success_message element?

The line that gives the error is the second last one.

It looks like it can not find that html element

Do you know How I could fix that?

you should add that element in html, in case that it is missing, or maybe it has a different name

I’m so sorry to take up your time but how do I do that? I’m just following the tutorial otherwise I don’t know much. Thank you

you should lean some basics about html, search that success_message string to see where else it is found

I found it on the other “file” (index.hmtl). I rewatched many times the code on the video but mine looks exactly the same.

ok, so it exists, now you can add some debugging with console.log to see what/why is not working

That’s what I got

I found the issue and I am ashamed… I had forgotten to put a #. I’m so sorry for wasting your time but thank you for you patience. However, I have a new issue now just when I thought I was done! I think this issue is specific to the tutorial so I’m not sure if anyone what is going on. Once the NFT is minted I open the link but I get this…

This is the adress given:

you could create a new forum post for this problem, it looks like that link is invalid with those undefined there