Adding Sandbox Tester in iTunes Connect with an existing Apple account

Question

I\'m trying to add sandbox testers in iTunes Connect. But I\'m getting this error:

The email address you entered already belongs to an existing Apple acco

Answer 1

Update June 2020

So Apple has decided in their infinite power trip to no longer allow the previous sub+email trick to work.

Big thank you to Josef Grunig in the comments for pointing out a new workaround, at least in Gmail.

You can still use the "." trick with gmail accounts: name.surname@gmail.com or namesurname@gmail.com without dot is the same account for Gmail while they are different for Apple Sandbox. Just tried and it worked.

This will allow you to have "multiple" email accounts all going to the same email, since you can put the "." anywhere in the email string before the @.

Example:
s.tandardappleid@apple.com
st.andardappleid@apple.com
sta.ndardappleid@apple.com
stan.dardappleid@apple.com
and so on, and Apple hopefully won't be able to kill this workaround since periods are allowed in email addresses normally.

If any other email providers allow this kind of functionality then feel free to include it in the comments.

---

The following has been left for historical record

---

Currently you cannot. The closest you can get is to use an email sub+address, if your email allows it. Gmail does for sure, others probably do too.

So if your normal itunes email is email@gmail.com, then you could set up a sandbox user like email+ios1@gmail.com and then do all the email confirmation and stuff in your normal inbox. This is useful because you don't have to create actual brand new address for the sandbox account.

This is still a huge pain though because itunes sees it as a seperate, unique account from your normal itunes account, and so if you want to try out the sandboxed app, you have to log out of itunes, log in with the new sub addressed account, and then when you are done testing you have to log out of the sub account and log back in with your normal account to have access to all your other apps.

Update April 2017

So I contacted Apple developer support, and after finally getting through their horrible Contact Us system, I got this reply back:

Thank you for reporting your sandbox issue.

Aliasing for sandbox testers is allowed if the main email is already registered in our system as being only a sandbox Apple ID.

The following is an example.

If standardappleid@apple.com is already registered as a regular account, you can not add standardappleid+alias@apple.com as a sandbox tester.

We will not be able to fix this for you as it is expected behavior.

I know it was working with normal apple id email addresses in Feb 2017. So now it looks like you'll have to have one address that is not associated with any Apple account in order to use sub addressing.

EDIT

Just to clarify a little more. If you use email@gmail.com as your main apple id, you can no longer use any variations of it with sandbox testing accounts.
Instead, Apple wants you to make a complete new and unnecessary email account such as email1@gmail.com that hasn't been used as an apple ID, and THEN use that one as your base email for the subaddressing. So once making email1@gmail.com, you could register email1+ios1@gmail.com, and email1+ios2@gmail.com, etc.

Answer 2

If you own a domain and can configure your mail server, many of them allow you to set a "Catch-All" mailbox that receives the e-mails destined to non-existing accounts. This way you can create addresses such as tester123@yourdomain.com and you'll get the verification e-mail.