Situation: When sending email to Gmail address, the client receives Undeliverable return email with error code 550. 5.7.26.
Suggestion 1: Contact your domain name and DNS manage company and have them to add DMARC record…SPF Auth….
Suggestion 2: Check that your domain’s SPF record includes the SMTP server that you have put in the SMA setting.
Suggestion 3: If yourdomain.com has no SPF record. Delivery from that domain will always be unreliable.
Suggestion 4: Domain name & server: land-com.net email sent from a @deanland.com address
Suggestion 5: Domain deanland.com has two SPF records which will cause errors. Please combine them unto one.
Suggestion 7:Check your SPF here https://mxtoolbox.com/spf.aspx
Suggestion 8: There’s a help document here:
If you follow the breadcrumbs back at the top of the help page you get a lot more help docs.
Seems like this would have come up before with ERP email system. If you want to do it the easy way, you might contact tech support for you ERP system, they’ve probably already figured this out.
Suggestion 7: I succeeded to fix this
550-5.7.26 Unauthenticated email from example.com is not accepted due to the domain’s DMARC policy
But the DKIM and DMARC are not the targets for fixing.
ERP fail as the domain of me@example.com designates 111.111.111.111 (ERP’s IP address) is not permitted, sender) smtp.mailfrom=me@example.comHow it solved:
1- Updated the code in ERP “send-email.php” file
$config = Array(
‘protocol’ => ‘smtp’,
‘smtp_host’ => ‘mail.example.com’,
‘smtp_port’ => 465,
‘smtp_user’ => ‘system-mail@example.com‘,
‘smtp_pass’ => ‘password’,
‘charset’=>’utf-8’,
‘validate’=>TRUE,
‘wordwrap’=> TRUE,
‘dkim_domain’ => ‘example.com’,
‘dkim_selector’ => ‘mail’,
2- Equipped the Mail service daemon on the ERP server with relay sending capabilities as shown in the below tutorial.
https://www.bonusbits.com/wiki/HowTo:Configure_SendMail_to_Use_SMTP_Relay
4- Updated the DNS records in the hosting company Cpanel to fit the modifications that were made.
– In the TXT section updated:
TXT Value: v=spf1 mx a ip4:000.000.000.000 ip4:111.111.111.111 ~all
TXT Value: v=spf1 mx a ip4:000.000.000.000 ip4:111.111.111.111 -all