My users cannot make payments through PayPal Adaptive Payments. Why?

It may depend on several reasons. We invite you to verify that your PayPal address has not been included in the receivers one.
It must be only set in the Primary Receiver entry of the plugin settings dashboard.
For any possible issue, you can submit a ticket at our support desk

I am encountering difficulties with Chained payment method: the commissions cannot be paid

This kind of payment uses WordPress Crons to make the automatic commission payments. Please, check that your server has not disabled them since this would undermine the correct functioning.

Does my Paypal account need to have a specific profile in order to use PayPal Adaptive Payments?

It is essential to have a Business Paypal account. For further information about the requirements for the correct functioning of the plugin, we suggest reading this page of the documentation.