Custom thank you page isn't working

I tried to make a custom thank you page but it won't work.

Your custom thank you URL is not correct. It has a space (%20) before the prefix.

Also the prefix should be http:// not http//

I put my cursor in the area in Settings to delete the space but there
wasn't one and I'm still getting the same issue.
...

OK, I logged into your account and modified your forms conditional settings. It seems you had a redirect condition.

So I disabled it. And your form is fully working now.