September 28, 2021

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? The IP address of the sender’s server is blacklisted in the receiver’s mail hosting server. The email address of the recipient does not

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