@leocg Yes, I use opera 119.0.5497.78 and macOS 15.4.1. The website works just fine on Safari and Chrome. They do give me a warning but there's an option to "proceed". In Opera, I can't find any option to proceed to the website.
@leocg - When I open Messenger in a separate tab, it works correctly and quickly. The issue only occurs when I use it from the sidebar. Interestingly, I also have WhatsApp on the same sidebar, and it runs smoothly without any delays. I don’t use other browsers—I only use Opera GX.