Users who have migrated their account (or who bought Minecraft recently) are not able to use this software, since it only has support for Mojang accounts.
Information on how to use the new accounts for authentication can be found here. Since it is quite complicated, for now you could add "offline mode" support as a temporary workaround in order for people to be able to playtest.
Users who have migrated their account (or who bought Minecraft recently) are not able to use this software, since it only has support for Mojang accounts.
Information on how to use the new accounts for authentication can be found here. Since it is quite complicated, for now you could add "offline mode" support as a temporary workaround in order for people to be able to playtest.