Why is hotjar 'verify installation' failing?

Question

Hotjar was working perfectly for a while, and without any changes to the site or hotjar setup, it reported that it hadn't received data for 24 hours and asked if I wanted to 'Verify Installation'.

But when I did, it times out with

Tracking code not found

Please check you’ve correctly pasted the Hotjar tracking code into your site’s header.

My code is precisely what I'm instructed to include (and it has't been modified, nor has anything else been modified that could be interfering):

<script>
    (function(h,o,t,j,a,r){
        h.hj=h.hj||function(){(h.hj.q=h.hj.q||[]).push(arguments)};
        h._hjSettings={hjid:1234567,hjsv:6};
        a=o.getElementsByTagName('head')[0];
        r=o.createElement('script');r.async=1;
        r.src=t+h._hjSettings.hjid+j+h._hjSettings.hjsv;
        a.appendChild(r);
    })(window,document,'https://static.hotjar.com/c/hotjar-','.js?sv=');
</script>

Why isn't hotjar able to verify installation even though it had no trouble in the past and nothing's changed?

Answer 1

This was a major PITA with such a simple solution.

When you click on 'Verify tracking code', it will send you to the site and the hotjar code will pick up the UUID parameter.

But if you have ad blockers (like uBlock Origin), then hotjar can't pick up the parameter and it won't work (it will time out).

So after a lot of wasted time, I figured out you have to turn off adblockers for it to work. If you're using uBlock Origin (as I was), click on the little addon icon (top right if using chrome), and click the big blue on/off button to disable it:

The try again, and it should succeed!