Often times, clients will share frightening looking "reports" from marketing companies telling them how "bad" their website is and why it is failing in the eyes of Google. Often, this is a sales tactic, but sometimes there is value here. Here is how to find it.
So - Some general advice around "Website audits":
1) They almost always find something. Expect this to be blown out of proportion to it's actual importance. No one gets 100%. Google.com only gets a 91/99 (mobile/desktop) on it's own pagespeed tool!
2) There almost always false positives. I've seen these tests fail our sites for something I know for a fact we do correctly.
3) Scores vary each time you run them. I'll see 0-100 scores on the sites that use that metric move +- 5 points every time i run the tests.
IMHO, the only meaningful way to approach these is to use a basket of tests, and compare them to your competitors. I personally like http://webpagetest.org, Google Pagespeed, and pingdom, plus some of the paid internal tools we use.
Also, see this as more of an indication of "ideas for things you could improve" rather than some damning score that is sentencing you to search engine irrelevancy. Just because you have a worse score on one of these tests, does not necessarily mean that sites with better scores will outperform you. There are many factors that determine that which are not measured by these tests.
Ask a reputable marketing company, hopefully one you already work with, for feedback on the tests. We get reports like this from our customers almost every week. 9/10 times they are scammy sales tactics, but sometimes they do find something useful that we can improve upon!
If you have received such a report, and you'd like us to take a look at it, please contact us and send it over!