Opera Software has rolled out an update to fix issues with Twitter website.
The problem was preventing Opera users from sending tweets, replying, retweeting, or seeing what is trending on the Twitter web app.
Opera has rolled out a fix through a browser JS file. It would be delivered automatically in the coming days.
You can also check for an update manually to force the browser to get it faster.
Opera developers said:
From the main menu, go to Help › Check for Updates. Click OK when seeing the message “You are using the latest version of Opera”. This will download an updated browser JS file, with the necessary fixes. Next, reload Twitter. If this does not solve the problem, you may have to restart Opera too.