Running Google Optimize when deploying Google Analytics using Tag Manager results in an error

Question

Running Google Optimize when deploying Google Analytics using Tag Manager results in an error

Update:

A / B tests work fine.
Redirection tests are running but not reported.

I have been following a Google article How to use Optimize when deploying Google Analytics with Google Tag Manager , but I keep getting the Google Optimize error message:

Something seems wrong. Your experiment works, but received visits.

I used the Analytics debugger and everything seems fine, so I ask you for help.
Here is my setup:

<meta charset="utf-8"> <script>dataLayer = [...]</script> //Page hiding snippet <style>.async-hide { opacity: 0 !important } </style> <script>(function (a, s, y, n, c, h, i, d, e) { s.className += ' ' + y; h.start = 1 * new Date; h.end = i = function () { s.className = s.className.replace(RegExp(' ?' + y), '') }; (a[n] = a[n] || []).hide = h; setTimeout(function () { i(); h.end = null }, c); h.timeout = c; })(window, document.documentElement, 'async-hide', 'dataLayer', 4000, {'GTM-XXXXXXX': true});</script> //Optimize container id //Requiring optimize in the analytics code, but not calling a pageview <script> (function (i, s, o, g, r, a, m) { i['GoogleAnalyticsObject'] = r; i[r] = i[r] || function () { (i[r].q = i[r].q || []).push(arguments) }, i[r].l = 1 * new Date(); a = s.createElement(o), m = s.getElementsByTagName(o)[0]; a.async = 1; a.src = g; m.parentNode.insertBefore(a, m) })(window, document, 'script', 'https://www.google-analytics.com/analytics.js', 'ga'); ga('create', 'UA-YYYYYYYYY-YY', {name: 'rollup', cookieName: '_rollupGa', allowLinker: true}); //Rollup analytics tracking id ga('rollup.require', 'GTM-XXXXXXX'); //Optimize container id </script> //Tag manager snippet <script> (function (w, d, s, l, i) { w[l] = w[l] || []; w[l].push({ 'gtm.start': new Date().getTime(), event: 'gtm.js' }); var f = d.getElementsByTagName(s)[0], j = d.createElement(s), dl = l != 'dataLayer' ? '&l=' + l : ''; j.async = true; j.src = 'https://www.googletagmanager.com/gtm.js?id=' + i + dl; f.parentNode.insertBefore(j, f); })(window, document, 'script', 'dataLayer', 'GTM-ZZZZZZ'); //Tag manager id </script>