If you’re using Incapsula (now Imperva) and NitroPack on your website, the following issue might appear in PageSpeed Insights:
Or you might see a verification prompt like this:
If this happens, please allow (whitelist) NitroPack’s IPs into Incapsula. You can find the IPs in this article.
Your hosting provider should be able to help you with this process. Just ask them to whitelist all the IPs from the above article into Incapsula.
After that’s done, purge your cache from the NitroPack dashboard and you should be all set.