Thanks for asking question! If you are seeing the message 'Your current account type is not supported'.
To add on this: This issue can occur if the account is registered in an unmanaged Azure AD directory, and it is not in your organization's Azure AD directory. To resolve this issue, sign up the Azure account by using another account, or take over the unmanaged AD directory.
For more information, see Take over an unmanaged directory as administrator in Azure Active Directory.
Check this link for more details for Troubleshoot issues when you sign up for a new account in Azure portal or Azure account center:
https://learn.microsoft.com/en-us/azure/cost-management-billing/manage/troubleshoot-azure-sign-up
Refer to this Quickstart: for creating an Azure notification hub from the Azure portal
Hope this helps.