โAre you entering the correct email?
The email entered must be associated with an existing subscription to receive a one-time Magic Link to the Subscriber Portal. If the email is not tied to a subscription on that store, Ongoing does not send out an email ( for security purposes )
Have you checked your spam filter?
Make sure to always check your spam filter in case your email client has rules and automations that might place this email elsewhere.
If you create a test order on your store, you can use that email to test out the Subscriber Portal login system.