I've been attempting to play on server lately, and 99.9% of the time get a "bad login" error from the servers, and I think the problem's on my end because of this:

Logging in with access token
Couldn't go online
net.minecraft.launcher.authentication.exceptions.InvalidCredentialsException: Invalid token.
at net.minecraft.launcher.authentication.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:123)
at net.minecraft.launcher.authentication.yggdrasil.YggdrasilAuthenticationService.logInWithToken(YggdrasilAuthenticationService.java:97)
at net.minecraft.launcher.authentication.yggdrasil.YggdrasilAuthenticationService.logIn(YggdrasilAuthenticationService.java:50)
at net.minecraft.launcher.ui.sidebar.login.NotLoggedInForm$1.run(NotLoggedInForm.java:162)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)