We seem to have issues accepting #Paypal payments since the old API certificate expired on the 1st of August.
We did update the certificate file but the shop software just silently never saved the update.
Sadly we did not get any errors from the shop software and the ToS of all payment providers prohibit us from clicking the button ourself to test things.
(For fraud prevention.)
A customer just informed us and within an hour we found a workaround for this bug.
Sorry for the inconvenience.