SMTP error from remote mail server after RCPT TO” error, and the fixes

Have you recieve message on the errors when you try to send emails to some of recipient. The error message that you received will share also the details of the errors. These errors can be occurred through many reasons and causes.

Here we will share the common errors and how to fix the error.

Causes & Solutions to fix SMTP error from remote mail server after RCPT TO error

1. Configuration error

SMTP error from remote mail server after RCPT TO:<user@domain.com>: host domain.com [xx.xx.xx.xx]: 550-Please turn on SMTP Authentication in your mail client. 550-(host.domain.com) [yy.yy.yy.yy]: __ is not permitted to relay through this server without authentication.

Cause: The cause of this error is because of misconfiguration of the mail client. Emails that sent without a valid authentication will trigger this error. This error also will occur if any mail server configuration issue, for example, the mail domain does not exist in the local domains file or the MX record mismatches.

Solution: The mail client settings should be properly configured with mail account details such as SMTP server and port number. For any customize PHP mail forms, using SMTP authentication to send out emails can help solve this error.

2. Domain Blacklist

SMTP error from remote mail server after RCPT TO:<user@domain.com>: host domain.com [xx.xx.xx.xx]: 550-"JunkMail rejected - host.domain.com [yy.yy.yy.yy]: ___ is in an RBL, see http://www.spamhaus.org/query/bl?ip=________"

or

SMTP error from remote mail server after RCPT TO:: host host.domain.com [xx.xx.xx.xx]: 554 5.7.1 Service unavailable; Client host [yy.yy.yy.yy] blocked using zen.spamhaus.org; http://www.spamhaus.org

Cause: Domain blacklist or RBL are used by most of the mail servers to prevent any spamming action occurs to their mail clients. When your mail server is getting listed in blacklist provider, they will blacklist your server IP also which that will cause this problem. Example of blacklist providers is Spamhaus, Baracudda and more.

Solution: Check your domain whether your domain getting blacklist or not, to check for the blacklist there are several free online services that you can use. Here we suggest you use MX toolbox to check for the blacklist and delist link. Delist process will take some time for it to be complete. Please check your mail server and pinpoint where is the source of the spam and fix the source then delist your IP from the blacklist provider.

3. Email Deliverability Issue (RDNS)

SMTP error from remote mail server after RCPT TO:<user@domain.com>: host mx.domain.com [xx.xx.xx.xx]: 554 5.7.1 <unknown[yy.yy.yy.yy]>: Client host rejected: envelope policy RBL PTRNUL

Cause : Invalid RDNS record will affect your email deliverability. RDNS pointer records are used to map IP to hostname and it helps to validate a server.

Solution : For WHM and cPanel user please check your email deliverability status :

WHM ----->Email>Email Deliverability
cPanel ----->Email>Email Deliverability

Check the DKIM, SPF & PTR record, make sure all this record is valid. If there any errors within the record please fix the issue using the Fix button in the area provided. Please note for PTR record one should consult with their Local IP provider to fix on this problem.

4. Recipient errors

SMTP error from remote mail server after RCPT TO: <user@domain.com>: 552 5.1.1 <user@domain.com> Mailbox delivery failure policy error
SMTP error from remote mail server after RCPT TO: 550 5.1.1 xxxxxxxx Recipient Suspended (TT999)
SMTP error from remote mail server after RCPT TO:<user@domain.com>: 550 5.1.1 <user@domain.com> Recipient not found.
SMTP error from remote mail server after RCPT TO:<user@domain.com>: host mx.domain.com [xx.xx.xx.xx]: 550 Requested action not taken: mailbox unavailable

Cause: These error main caused by a variety of issues at the recipient mail server. The errors might be because of missing or suspended recipient email account, incorrect MX record, blacklist on recipient IP, the mailbox of the recipient full and unable to process new email.

Solution : To solve this issue, copy the error message and find any other means to contact them and forward the message to them.

5. Wrong email address

SMTP error from remote mail server after RCPT  TO:<user@domain.com>: host host.domain.com [xx.xx.xx.xx]: 554 5.1.8  <user1@domain1.com>: Sender address rejected: Domain not found
SMTP error from remote mail server after RCPT TO:<user2@domain2.com>: host mx.server.com [xxx.xxx.xxx.xxx]: 550-Verification failed for <user1@domain1.com> 550-No Such User Here : Sender verify failed

Cause : This errors can be cause by a simple reason such as in the message. The domain name not exists, suspended, wrong email. Other reason is there might be an error on the email recipient like the email address is not exists.

Lastly…

If you believe that none of the above that can cause the errors, copy the bounce message and create a new ticket on your account to us. We can help to check and resolve your issue. Click here to create your ticket.

A very soft reminder, its never hurt to backup your exim db first. Incase there be any error you can rebunk it.

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