I was trying to create a request, but because I was doing it from an iOS account, the first letter of the email address in the administrators box was being capitalised.

I kept getting an error message telling me that the administrator emails must be approved emails, and only digging through the code did I realise what the issue was.

I suspect that since in almost all modern mail implementations, the inboxes are case insensitive, that the regex should allow uppercase letters.