Since 12 august I have problems with sending mail to Gmail : I get failure notices, but sometimes after a few days the mails do arrive.
108.177.119.26 failed after I sent the message. Remote host said: 421-4.7.0 This message does not have authentication information or fails to pass 421-4.7.0 authentication checks. To best protect our users from spam, the 421-4.7.0 message has been blocked. Please visit 421-4.7.0 https://support.google.com/mail/answer/81126#authentication for more 421 4.7.0 information. n3-v6si1447282edq.35 - gsmtp I'm not going to try again; this message has been in the queue too long.
But I do not understand or get through to the google support link :( :(
All Replies (1)
I clicked the link in your post https://support.google.com/mail/answer/81126#authentication
it took me to a Google information page for bulk senders. What do you see when you click the link?
My guess is you are using a gmail account to send email for a non @gmail.com email address. But really I am just guessing because you have provided no information on what you are or are not doing to trigger the message.
If you are sending to google addresses they have the following information on their linked page Authenticate your mail
Emails without authentication often get rejected or marked as spam to protect recipients from phishing scams. Unauthenticated emails with attachments might get completely rejected for security reasons.
To ensure Gmail can authenticate you:
Send from the same IP address Keep valid reverse DNS records your IP address that point to your domain Choose the same address in the 'From:' header for every bulk message
Other recommendations
Sign messages with DKIM. We don't authenticate messages signed with keys that use fewer than 1024 bits. Publish a SPF record. Publish a DMARC policy.
Learn more about email authentication. IP guidelines
The sending IP must have a PTR record (i.e. a reverse DNS of the sending IP) and match the IP obtained via the forward DNS resolution of the hostname specified in the PTR record. The sending domain should pass either a SPF check or DKIM check.
Two of the big issues with using Google to send mail for say @mydomain.com is that Google is not recorded in DNS as the mail sending server for that domain. hence a reverse DNS check does not validate. The other is if you are sending a lot of mail your account might be blacklisted as a spammer.