TL;DR You can't use a Yahoo or AOL email address in the tinyEmail sender details form.

Look at the above screenshot. tinyEmail blocks users from entering a Yahoo or AOL sender email address. And boy do we have a good reason: these email addresses can hurt delivery rates because the servers that receive those messages might flag them as spam.

The cause of the problem is a DMARC (Domain-based Message Authentication, Reporting, and Conformance) record. Yahoo was one of the first email box providers to use a DMARC record. AOL did the same thing soon after. Now many do, too.

This record is a text file added to the DNS of the email service provider. That record tells receiving servers what to do if an email message looks like spam.

What does spam look like to a computer? One characteristic is mismatching domains. If the domain of your sender email address is different from the server sending the message, well, that's what spam looks like at first glance.

So, let me bring it back to you and tinyEmail. Say you enter a Yahoo email as the sender address, and your campaign is sent from the tinyEmail domain. How might a giant supercomputer scanning a quadrillion emails per day evaluate that domain mismatch? Suspiciously, I'd guess.

So now you have a suspicious email. What happens next? That's where the DMARC record comes in, and the results aren't pretty.

The DMARC record tells the receiving server what to do if DKIM or SPF authentication fails. The choices are often spam the message, block the sender's email address, or deliver to the recipient.

We work hard to protect our rep and prevent spamming whenever possible. That includes stopping tinyEmail customers from entering Yahoo and AOL addresses as the sender email. Yup, that might inconvenience a few people, but the benefits help all tinyEmail customers in the end.

If you have any questions, get in touch with our support team!