When is the email link sent to the client from CraftHub? Do you wait for some confirmation from paypal that funds have been Payed and Received before you send the link out to clients?
Your client will receive an e-mail regardless of what their payment type is immediately after purchase. If your customer has not yet paid for their order they will not be able to log in, instead they get an error message saying that their payment has not yet been confirmed. Once you mark the order as paid in your Etsy "sold orders" your customer will be able to log in.
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