Welcome to the Make community!
You inserted an Absolute (full) URL into the URL field.
If you read the description below it, it says:
Enter a path relative … for example …
So you simply need to omit the first part that will be added for you.
Hope this helps! Let me know if there are any further questions or issues.
— @samliew
P.S.: Did you know, the concepts of about 70% of questions asked on this forum are already covered in the Make Academy. Investing some effort into it will save you lots of time and frustration using Make later!