How to Fix “550 Permanent failure for one or more recipients” SMTP error?
We have received lots of requests from our clients regarding the “550 permanent failure for one or more recipients error”. This is an SMTP (Simple Mail Transfer Protocol) error and this error mainly occurs when the sending mail gets blocked by the receiving mail hosting server. What causes 550 permanent SMTP errors? How to fix 550 permanent SMTP errors? If your server is sending spam frequently or any phishing emails, then the IP of your