Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain ——- by ———-..The error that the other server returned was:
554 5.7.1 Service unavailable; Client host [18.104.22.168] blocked using rbl.abuse.ro; your IP seems infected and sending spam; please go away
p.s. IP-ul, pentru curioși, e din Mountain View.