You can’t really “sync” Opera GX and a Roblox account the way you sync two apps. Opera GX is just the browser; your Roblox login lives in Roblox, not inside Opera GX.

What you can do

  • Open Opera GX and go to Roblox’s website.
  • Log in with your Roblox username and password.
  • If you click a game to play, Roblox will usually hand off to the installed Roblox app/player rather than running fully inside the browser.

If you want account access

  • Use Opera GX to browse Roblox, check messages, friends, groups, inventory, and trading.
  • Keep your Roblox account logged in on the Roblox site if you want faster access in the browser.
  • Opera GX syncing only applies to Opera data like bookmarks, tabs, passwords, and settings, not to Roblox itself.

If it is not working

  • Update Opera GX.
  • Clear cookies/cache for Roblox.
  • Make sure your system date and time are correct.
  • If Roblox keeps refusing to open, try the Roblox app or player directly, since browser-only play is limited.

Quick answer

If your goal is to use Roblox in Opera GX, just log into Roblox through the browser; there is no special “sync” button between the two.

TL;DR: Opera GX can access Roblox, but it does not sync with your Roblox account. Use Roblox’s login page in Opera GX, and the actual game usually opens through the Roblox app/player.