If birthday version worked earlier, then nothing has changed in the game itself. That's probably something on your side. 'Other browsers' on ios are basically just wrappers around safari.
Unfortunately this isn't going to get fixed soon, as you're the only person reporting the problem and on this stage I have no idea what happens to you. On which stage the game fails? Do you get any error messages? I guess you're running it on mobile, so no console logs are available. This might be related to cache issues, or some software updates, or phone settings, or anything.