PSA: Since we just ran into some issues, let me address them.
Please check if you're still part of a family group, if so, you need to leave it before I send you an invite.
Secondly, make sure to use the email for your Nintendo account, ideally copy and paste it exactly as it shows in your account settings. We had an issue of upper/lower case, it will only send an invite email if it's an exact match.