Apparently it is PayPal and not ipernity.
A message from PayPal to another site operator includes, "our engineers are investigating this problem".
Please delay your renewal until the blue banner message is changed to signal the ok.

If your membership is going to end within a day, then the Donate link in the footer of ipernity pages does enable a payment to be made.
It may force you to input the amount in euros, for 1 year standard this is €49.90, and for 6 months it is €24.95
If you use this method, then please send us a help ticket with the transaction id.