Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Cannot send emails to Gmail users

  • 1 reply
  • 1 has this problem
  • 1 view
  • Last reply by david

more options

So I am getting this message everytime I send emails to any gmail user.

Delivery to the following recipients failed permanently:


Reason: There was an error while attempting to deliver your message with [Subject: "Tacoma Wheels and Tires"] to. MTA p3plsmtpa12-09.prod.phx3.secureserver.net received this response from the destination host IP - 209.85.232.26 - 550 , 550-5.7.26 This message does not have authentication information or fails to 550-5.7.26 pass authentication checks. To best protect our users from spam, the 550-5.7.26 message has been blocked. Please visit 550-5.7.26 https://support.google.com/mail/answer/81126#authentication for more 550 5.7.26 information. b33-20020a05620a272100b0067d3b4ad74asi2031678qkp.731 - gsmtp .

So I am getting this message everytime I send emails to any gmail user. Delivery to the following recipients failed permanently: Reason: There was an error while attempting to deliver your message with [Subject: "Tacoma Wheels and Tires"] to. MTA p3plsmtpa12-09.prod.phx3.secureserver.net received this response from the destination host IP - 209.85.232.26 - 550 , 550-5.7.26 This message does not have authentication information or fails to 550-5.7.26 pass authentication checks. To best protect our users from spam, the 550-5.7.26 message has been blocked. Please visit 550-5.7.26 https://support.google.com/mail/answer/81126#authentication for more 550 5.7.26 information. b33-20020a05620a272100b0067d3b4ad74asi2031678qkp.731 - gsmtp .

All Replies (1)

more options

This is generally an error of the domain information. The gmail server sees email incoming from domaina, yet the ip of smtp server is from domainb (probably a web host company). This can look like spam if the domainb does not have settings that tie it to domain a (normally DKIM and SPF settings). I suggest checking with your website host provider.