Hi @anon79295466, welcome to the Asana Community Forum!
In order to investigate this further, I recommend you to contact our support team: How to contact our Support Team ✉. Unfortunately I don’t have the tools in the forum to verify why you are not receiving the invitation.
When you contact them, please send them the URL of this thread and confirm the email address of the user you are trying to invite to speed up the process.
I hope the issue is solved soon! Let me know if you have any other questions!