Adding Sandbox Tester in iTunes Connect with an existing Apple account

Solution 1:

Update by Dimitar Nestorov May 2021

I just tried the sub+email trick and it works again. (Not confirmed by OP)

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: [email protected] or [email protected] 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:
[email protected]
[email protected]
[email protected]
[email protected]
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 protected], then you could set up a sandbox user like [email protected] 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 [email protected] is already registered as a regular account, you can not add [email protected] 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 protected] 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 [email protected] that hasn't been used as an apple ID, and THEN use that one as your base email for the subaddressing. So once making [email protected], you could register [email protected], and [email protected], etc.

Solution 2:

The errors

The email address you entered already belongs to an existing Apple account. Please try again.

and

An unknown error has occurred.

and

An error has occurred. Try again later.

are equivalent.

It means that your email address is not accepted. The email field may also be highlighted red when the error message is shown.

Apple blocks these email addresses (this is undocumented):

• Existing Apple accounts
• Existing Apple accounts with the Gmail + trick added to the sandbox user account
• Mailinator
• Mailinator alternate domains
• Other, undocumented stuff

I'm just going to post the real solution here, since this is what other people are wanting to know:

ANSWER

1. Login to MyDomain, or GoDaddy or whatever you use to manage your personal domain (if you don't control any domains you can turn in your nerd card now)
2. Create a new MX record for anon.yourdomain.com and point it to mail.mailinator.com. Or, possibly, realize that you already did this a while ago for some previous reason
3. Register the sandbox with some email like [email protected]
4. Then you're done

Solution 3:

I fixed this by creating a brand new (free) Google account [email protected] and adding that as a new sandbox tester. This makes a new Apple ID for that email address. It's a pain but it worked.