Oh cmon. What is taking so long to fix that? If this issue would also be on Windows you guys would have probably fixed it within the next day. But its just on linux so we don't care, we won't put that many resources into that because there are less linux users anyways and why can't they just shut up and switch to windows. And no please don't say that that's not true, cmon guys, minecraft is owned by microsoft.
With beta 2.3.520 it now shows an error message.Can't download the files, the problem is serverside. Server responds with 403. Same thing with legacy.json btw.If you already have the legacy.json and 1.8.9.jar downloaded everything works just fine.EDIT: Idk how but after clearing the .minecraft folder and reinstalling the launcher it is working again. (For anyone having the same problem. don't forget to enable the beta version again after reinstalling :3)