So, you are trying to test your iPhone In App Purchase, and you are getting this error message when creating the test account in iTunes Connect: "
This is apparently a bug in the iTunes Connect UI or server, not sure. It happens for me with both Safari and Chrome. I have not tested other browsers.
Here is the solution....Enter all of your dummy information for the test account and hit submit. You will receive this error. Next, simply change the email address to a different bogus email address and re-submit. It should work.
Another error you may see is: " This error is more legitimate and implies the email address is already registered with Apple. Just change the email address to something different and re-submit.
Note also there is some suggestion out there that you are only allowed to have 1 test user per country. I did notice that when using different countries when setting up test users, this error did not occur. So, there could be some validity to this suggestion (even though it seems ridiculous).
Hope this helps!