Your Manual URL is insecure / no or bad SSL certificate:
LilGames Thanks, where did you see that link? The correct url is http not https.
Anthony Where? In your asset store listing: https://assetstore.unity.com/packages/tools/gui/tutorial-engine-easy-step-by-step-tutorial-creator-148854
It's been at least a couple years now that "the web" has deprecated http in favor of https (with most web hosts even offering free SSL certificate). Browsers show warnings for sites still using http.
LilGames Thanks I edited the page. This is only used as a redirection, I don't need https here.