At present e bay is full of technical glitches, you, like myself and 100's of others  are lucky just to be able to sign in and view items.As a seller at the moment  I am experiencing difficulties in invoicing,  the e bay invoice page has stopped calculating my buyers postage rate (Means I have to trundle off to Australia Post web site, and manually calculate postage, then enter this on invoice and send to my buyer), I have received payments  from 2 buyers today through Pay-pal so I don't think your issue is a Pay-pal problem.I would send your seller a message requesting an  invoice to pay, once sent you should receive a copy of this in your actual email. inbox.Depending on how your seller set up their listing, they may have to manually send you an  invoice,rather than the  auto e bay generated invoice (which maybe faulty).For some reason the Pay-pal system is not accepting your payment after you select the payment button.I would say it is a issue with e bay.As I said, try messaging your seller first and see if they can assist, and maybe check the feedback boards, as currently there are alot of technical glitches and solutions posted by other e bay members.