'Unknown Error' while completing Microsoft ISV Success Sign Up

While completing my ISV Success signup, after pressing 'Agree and Continue' and verifying all input fields, it shows me "An unknown error occurred, please try again later".

Why is it showing this error? All the fields have been filled correctly. 

Can someone assist me with this? Has anyone else faced and resolved this error?

I have attached the screenshot of the error as well.

Thanks.