Why is the email address is invalid
Question marked as
Hello,
Was this screenshot from the process of creating a new Apple ID? If so, I believe the below info explains why an address would be invalid. Are you sure you don't already have that email address as an existing Apple ID, an additional email with an Apple ID, or a rescue email address?
Change your Apple ID - Apple Support
"If you see a message that the email address you want to use isn't available or is already in use, check that you or a family member aren't already using that email address with a different Apple ID. If a family member is using that email address, remove it from their account then try to use it."
About your Apple ID email addresses - Apple Support
I hope this helps.