SPF records can be confusing to setup, and if email messages that were intended for your mailbox were blocked because of an SPF record is can be difficult to explain to the sender why it happened. 

Previously when a message was rejected for an SPF policy violation the sender was sent to: https://support.duocircle.com/solution/articles/5000701435-inbound-spf-failure

Now we will be sending the sender to the OpenSPF.org website where they will be able to see diagnostic information with suggestions on what they need to do on their side to correct the issue. Here is an example message that the recipient will see: