Unfortunately BitPay doesn't show the actual address in the invoice. It only gives a link (payment protocol?) which Electrum is supposed to use to autofill the amount and address etc. Apparently there is a CA (no idea what that is) in the information that Electrum receives which it does not accept because it is "Not Found in Trusted CA Store".

According to a BitPay support article it should be able to accept a peer-to-peer payment but I dit not see that option when I was trying to pay.