This is happening to me as well. I'm a proud user of a Motorola v9x, and I was shocked to find out (a few years ago) that it will perfectly play videos from Youtube (albeit sometimes the vid and audio don't sync well) and I can access my twitter account as well.
As usual, every couple of years, the devs at google decide to F%&# with my phone and remove a feature.
I've checked and UC Browser 9.0 (which looks like it steals opera mini's source code) works fine!
Please please please fix. No matter what happens I'll still use my little mp3 playing v9x. I'm attached to it!!