In the past, users may have encountered problems sending emails to some large external mail providers, such as:
This is often down to the large quantities of emails sent from our platform to these providers. Our teams ensure that the reputation of our IP addresses remains clean, but additional steps may be required by those who use our mail platform if you encounter problems sending emails to these providers.
If you attempt to send an email to a provider listed above and receive a message such as: 421 Too many messages, then it's possible the server you're sending from has been rate limited or blocked by a provider. These blocks generally last anywhere from 24-48 hours, and allows providers such as ourselves to mitigate any spam that could have caused the issues.
One thing you can do is add an SPF (Sender Policy Framework) record whenever a domain is set up to use our mail servers.A better example of an SPF record for use with our systems is:
v=spf1 exists:%{i}.mta.spf.extendcp.co.uk exists:%{i}.web.spf.extendcp.co.uk -all
This should be added as a `TXT` record within the DNS with the `hostname` field left blank.
Additionally, you can try sending from a different mail server. All of our mail servers allow SMTP authentication regardless of your assigned incoming mail server. If you're unsure where to locate a mail server, our support teams can assist.
Failing that, our webmail platform sends from different IP addresses than our mail servers, and can be used to send an email.
Article ID: 713
Created On: Thu, Feb 14, 2019 at 9:25 AM
Last Updated On: Thu, Feb 14, 2019 at 9:44 AM
Online URL: https://www.heartinternet.uk/support/article/why-have-my-emails-been-rejected-by-another-email-provider.html