Whenever I launch VRChat, I just get this infinite loading screen. It signs me in, like normal, and then it goes to this blank screen, (image attached). It keeps playing the loading music, and then every now and then I hear the error sound. Help GREATLY appreciated.
Press your Windows key and type “cmd” into your Windows Search bar. Right click “Command Prompt” and click “Run as Administrator”. After accepting the UAC prompt, a black command prompt window should pop up. Copy this command with Ctrl-C, and paste it into the window by right-clicking in the window.
rmdir /S /Q "%AppData%\..\LocalLow\VRChat\vrchat\Cookies" 2>nul & rmdir /S /Q "%AppData%\..\LocalLow\VRChat\vrchat\HTTPCache" 2>nul & rmdir /S /Q "%AppData%\..\LocalLow\VRChat\vrchat\Unity" 2>nul & rmdir /S /Q "%AppData%\..\LocalLow\VRChat\vrchat\VRCHTTPCache" 2>nul & rmdir /S /Q "%TEMP%\VRChat" 2>nul & rmdir /S /Q "%UserProfile%\.cache\youtube-dl" 2>nul & REG DELETE HKCU\Software\VRChat\vrchat /va
Press Enter. A bunch of files will show as being deleted. It will then ask you if you want to delete all keys under the VRChat key. Press Y for Yes, and press enter.
This worked for me so hope this helps 
https://help.vrchat.com/kb/article/17-i-crashedcant-launch-vrchatother-issues/
theres the link to if u need it
Had this identical scenario, was pulling my hair out, because it happened to me no matter what machine I tried from. I could log into anything VRChat related, the website, the SDK from within Unity, everything, EXCEPT VRChat itself.
Finally dropped VRC tech support an email detailing the issue, and my logs, and just as I thought, the issue was indeed on their end, not mine. They did one thing, and told me to try again, and bam, I got right on.
i Think im having this problem, i did the same thing the person above me did just a couple of seconds ago, probably with less information though, and i tried the command thing but that didnt seem to do anything
The redistributable worked wonders and fixed this exact issue for me, thank you so much!