HTTP/2 serves your page's resources faster and with less data moving over the wire.
How the Lighthouse HTTP/2 audit fails #
Lighthouse lists all resources not served over HTTP/2:
Lighthouse gathers all resources requested by the page and checks the HTTP protocol version of each. There are some cases where non-HTTP/2 requests will be ignored in the audit results. See the implementation for more details.
Each Best Practices audit is weighted equally in the Lighthouse Best Practices Score. Learn more in The Best Practices score.
How to pass this audit #
Serve your resources over HTTP/2.
To learn how to enable HTTP/2 on your servers, see Setting up HTTP/2.