Why is the browser blocking the connection of the script?

Question

Browser extensions

I'm trying to connect ads to an extension that will replace the standard Vkontakte ads. In my extension, the script is inserted into the page via script. But the browser is blocking it for some reason. The page itself is loaded via https, while the script was accessed via http. But after that it was fixed and the script became available via https. Despite this, the browser continues to block the script. Why is this happening?

[blocked] The page at 'https://vk.com/audios184918649' was loaded over HTTPS, but ran insecure content from 'http://https//ads.actionteaser.ru/news.js/news.php?sid=2176&bn=N3FeJdgGFLDh…%E2%E0%20|%207%20%E0%F3%E4%E8%EE%E7%E0%EF%E8%F1%E5%E9&cookie=null&cls=null': this content should also be loaded over HTTPS.