(this post is for people who want to use companion app with Opera, I hope it can be useful)
Guys I use Opera browser and for me companion app has always worked perfectly, but few days ago I did the browser upgrade (to 75.0.3969.149 version) and companion app didn’t work more. So, I tried a lot of things but the only solution is upgrade Opera to the previous version and now companion app works great (but I have blocked the auto-upgrade of Opera, you cannot do this by Opera’s settings, but how below tutorial explains).
The Opera’s version I use now is 74.0.3911.75
You can find it to the end of this web page: Index of /ftp/pub/opera/desktop/
You NO need to uninstall Opera, just download the version above and install it, then NO open Opera, but follow this tutorial that explain you how to block Opera’s auto-upgrade:
Enjoy