How can I get my original form URL again?

I made a custom url and now I want to import that form but I'm getting the error message that the "Form id is missing or irregular." From other discussions I've read, it looks like I need to import using the non-customized URL. Can I get that back or am I out of luck?

Do you have access to the account where that form was created?

If so, you can try undoing the custom URL by clicking on the undo button on the publish page.

Follow the last step of this guide:

How to Create a Custom URL of a Form?

Thank you! That was very helpful.

Very welcome