SPF verification still showing a warning after SPF has been updated

Question

Why do I still see the verification warning after I've updated my external address's SPF record? 

Answer

You must retry the SPF check after updating the record to verify the SPF settings. To do so:

1. Navigate to Admin > Channels > Email.
2. Select the address displaying the warning. 
3. From the options that display, select Retry next to the SPF check.