I had hoped to login with my Mojang/Microsoft account in the mod dev environment (IntelliJ IDEA), using

--username [username] --password [password]

, however when doing so I immediately get the following exception at runtime, and the program terminates:

com.mojang.authlib.exceptions.AuthenticationException: Migrated
	at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:119) ~[authlib-2.1.28.jar:?] {}
	at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:99) ~[authlib-2.1.28.jar:?] {}
	at com.mojang.authlib.yggdrasil.YggdrasilUserAuthentication.logInWithPassword(YggdrasilUserAuthentication.java:92) ~[authlib-2.1.28.jar:?] {}
	at com.mojang.authlib.yggdrasil.YggdrasilUserAuthentication.logIn(YggdrasilUserAuthentication.java:75) ~[authlib-2.1.28.jar:?] {}
	at net.minecraftforge.userdev.LaunchTesting.login(LaunchTesting.java:160) [forge-1.16.5-36.2.2_mapped_official_1.16.5.jar:?] {}
	at net.minecraftforge.userdev.LaunchTesting.main(LaunchTesting.java:80) [forge-1.16.5-36.2.2_mapped_official_1.16.5.jar:?] {}
Exception in thread "main" java.lang.RuntimeException: com.mojang.authlib.exceptions.AuthenticationException: Migrated
	at net.minecraftforge.userdev.LaunchTesting.login(LaunchTesting.java:163)
	at net.minecraftforge.userdev.LaunchTesting.main(LaunchTesting.java:80)
Caused by: com.mojang.authlib.exceptions.AuthenticationException: Migrated
	at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:119)
	at com.mojang.authlib.yggdrasil.YggdrasilAuthenticationService.makeRequest(YggdrasilAuthenticationService.java:99)
	at com.mojang.authlib.yggdrasil.YggdrasilUserAuthentication.logInWithPassword(YggdrasilUserAuthentication.java:92)
	at com.mojang.authlib.yggdrasil.YggdrasilUserAuthentication.logIn(YggdrasilUserAuthentication.java:75)
	at net.minecraftforge.userdev.LaunchTesting.login(LaunchTesting.java:160)
	... 1 more

 

Is it currently possible to use migrated accounts, or is this something we'll have to wait for? Thanks.

with Mojang account is was possible,
but it's not possible with a Microsoft account

Let's hope that changes in the future, of course.

Just the word "Migrated" certainly doesn't make for a particularly helpful exception message; having migrated your account is hardly an error in-and-of itself since that's what they (Mojang) would like everyone to do, and the message tells us absolutely nothing about what actually went wrong or why. Just another example of their poor programming.

6 minutes ago, Logix said:

Just the word "Migrated" certainly doesn't make for a particularly helpful exception message; having migrated your account is hardly an error in-and-of itself since that's what they (Mojang) would like everyone to do, and the message tells us absolutely nothing about what actually went wrong or why. Just another example of their poor programming.

I think that will be possible again, when the most accounts have been migrated, maybe 1.18