Email address not valid for Apple Account creation

If an email address has been used for a different account and then that account is closed, you may have to wait 6 years before it can be used again. You may also not be able to use it if it is in use as a notification address for an account.

Here are related articles, though they can be a bit confusing to follow:

Change your Apple Account primary email address - Apple Support

- If you remove an email address that isn’t an iCloud email address from your Apple Account, it can’t be associated with another Apple Account for 30 days for security reasons. After removing an email address from your account, notify anyone who might contact you on Messages, FaceTime, or other Apple apps using that Apple Account email address. After 30 days, another user might be able to associate that email address with an Apple Account for Messages, FaceTime, and more.

If you can’t change your Apple Account primary email address

- If you try to change your Apple Account to an @icloud.com email address that was created within the last 30 days, you will be asked to try again later.

- 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 Account. If a family member is using that email address, remove it from their account, then try to use it.

From: How to delete your Apple Account - Apple Support

“Can I use the primary email address for my deleted Apple Account to create a new Apple Account or with another existing Apple Account?

No, once your Apple Account is deleted, you can’t use the email address that you used with it to create a new Apple Account for as long as Apple retains the one-way hash of the email address. For third-party (non-Apple) domain accounts, the one-way hash is deleted after six years. For other accounts, this is retained according to Apple's retention policy, which is reviewed regularly. In addition, you can’t use that email address with another existing Apple Account except as a rescue email. Also, if your primary Apple Account email address is with a Custom Email Domain, it can never be reused to create an Apple Account after your Apple Account is deleted, even if the domain ownership changes.”

For information that detailed you would need to ask Apple.

Refer to this page for Apple Support features ➔ Contact - Official Apple Support

Select from the presented options until you find a solution for your issue, or see if there is a chat or phone call contact method offered lower on the page under “Get more help” (you sometimes have to narrow down the options multiple times before this is shown). If you do not see your issue, keep experimenting with any series of selections until you reach one that offers a chat session or a telephone call and get the representative to redirect you.

This support article has various country telephone numbers for contacting Apple for support and service ➔ Contact Apple Support - Apple Support Scroll down to “Connect with live support”. If your country is not in the list, go to the “Other countries” entry at the end of the list. Not every country has telephone support, and phone numbers may only work when calling from the same country.

For chat, you can try using the Apple Support App —> https://apps.apple.com/app/apple-support/id1130498044

For chat help with a USA Apple Account —>

https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0998&symptom_id=20198