Can't create itunes connect sandbox tester

There are many topics (Old and new) related with this. Unfortunately I am having a lot of problems to create a simple Sandbox Tester Account.

My error is:

There are one or more validation errors below.

The problem is that what the message says is false, there are no indications about what is wrong.

I have made many attempts:

• Use an account that exists as an internal tester by testlight.
• Create an account from an existing gmail account.
• Create a new account with domain @icloud.

But nothing works. :(

I have also tried that the passwords have some capital letter, some special character and numbers.

Even i adding +something in email but the error changes to

An error has occurred. Try again later.

I'm trying to follow all recommendations from the next threads:

https://forums.developer.apple.com/message/349819#349819

https://forums.developer.apple.com/message/349820#349820

Can't create itunesconnect sandbox tester

I was able to create sandbox tester now.

I was doing something wrong in the process. To fix it you need to put a completely new account.

Let me explain explain:

This form apparently creates a new apple account. But it's not.

Just create the account first here, then login with this email on your iphone and finally, you need to create a gmail account to verify the account.