If a substantial amount of the affiliate traffic (affiliated link clicks) is invalid due to an EMPTY_REFERER
error, most likely, it’s related to one of the following issues:
rel=”noreferrer”
WordPress 4.7.4 comes with a security addition to TinyMCE which automatically adds a rel=”noreferrer”
attribute to all links. The special directive explicitly hints the browser to not share the referrer URL with the target page, which means that unless you set your Affiliate Program terms to allow traffic from anywhere if the referrer is missing the traffic will be considered as invalid. The fix is very simple: ask your affiliates to remove the noreferrer
tag from the affiliated links:
Good: <a rel=”noopener” href=”//r.freemius.com/123/456/”>text</a>
Bad: <a rel=”noopener noreferrer” href=”//r.freemius.com/123/456/”>text</a>
Inconsistent Protocol with Default Referrer Policy
When a Referrer Policy of the linking site is not set the policy defaults to no-referrer-when-downgrade
. This policy determines that the referrer is only sent when the protocol security level stays the same. This means that if the affiliated link is HTTP and the page is loaded via HTTPS (or vice versa) the referrer won’t be sent, due to the difference in protocol security level. To avoid this situation tell your affiliates to simply use links without specifying the protocol:
Good: <a href=”//r.freemius.com/123/456/”>text</a>
Bad: <a href=”https://r.freemius.com/123/456/”>text</a>