Affiliate's payment details not specified
You can't click Process payment if Affiliate payment details hasn't been entered, it will show No payment method specified in red:

In this case, you need to contact your affiliate to fill in their payment details.

To avoid this situation, we have prepared a default text in the Affiliate guide:
Hello Affiliate,
Please update your Payment method in Settings > Payment. If your payment detail is not specified, you will not be able to receive commission.
Best regards,
Last modified 2yr ago