Cannot connect to Paypal

I have a regular PayPal business account, I don’t think it’s a merchant account though in the traditional sense of accepting card payments. Is this supported? It looks like I should just be able to connect to Paypal, but I just get error messages from Paypal as I try to login and connect.

Solved using the browser on a Windows system despite a clunky loop of Paypal login screens; the Android browser just causes PayPal to fail with an error page.