550-5.7.1 [217.70.178.231] Our system has detected that this message is not RFC 550-5.7.1 5322 compliant: 550-5.7.1 ‘From’ header is missing. 550-5.7.1 To reduce the amount of spam sent to Gmail, this message has been 550-5.7.1 blocked. Please visit 550-5.7.1
gmails being retuturned with this message attached.
This mail is unauthenticated, which poses a security risk to the
550-5.7.26 sender and Gmail users, and has been blocked. The sender must
550-5.7.26 authenticate with at least one of SPF or DKIM. For this message,
550-5.7.26 DKIM checks did not pass and SPF check for [labertouche.com] did
not 550-5.7.26 pass with ip: [203.30.68.68]. The sender should visit
550-5.7.26 Prevent mail to Gmail users from being blocked or sent to spam - Gmail Help for
550 5.7.26 instructions on setting up authentication.
550-5.7.1 [217.70.178.231] Our system has detected that this message is not RFC 550-5.7.1 5322 compliant: 550-5.7.1 ‘From’ header is missing. 550-5.7.1 To reduce the amount of spam sent to Gmail, this message has been 550-5.7.1 blocked. Please visit 550-5.7.1
See this Google support page on that error. I would suggest to contact Google via either their community or phone tech support for assistance as to why it’s blocked. Not an eM Client issue.
550-5.7.26 DKIM checks did not pass and SPF check for [labertouche.com] did
not 550-5.7.26 pass with ip: [203.30.68.68].
DKIM and SPF were implemented this year to prevent spam & spoofing etc to Personal Gmail mailboxes. Microsoft also implemented a similar thing this year for their personal mailboxes.
So you have to advise the technical support staff (who own that domain) to update the mail servers & domain mailboxes to support DKIM & SPF for sending mail to Gmail as per that error message you are getting. Not an eM Client issue.
Note: Alot of older mail servers & domains will need to update to support these standards.