The launcher does not start.

There is a unhandled exception:

14:02:38 FATAL]: Unhandled exception in thread Thread[pool-2-thread-2,5,main]
com.google.gson.JsonSyntaxException: duplicate key: null

Please tell me how can I fix this or how check what is wrong. Thank you.

Here details:

Starting launcher.
[14:02:33 INFO]: Minecraft Launcher 1.6.89-j (through bootstrap 5) started on linux...
[14:02:33 INFO]: Current time is Sep 15, 2019 2:02:33 PM
[14:02:33 INFO]: System.getProperty('os.name') == 'Linux'
[14:02:33 INFO]: System.getProperty('os.version') == '4.9.0-9-amd64'
[14:02:33 INFO]: System.getProperty('os.arch') == 'amd64'
[14:02:33 INFO]: System.getProperty('java.version') == '1.8.0_221'
[14:02:33 INFO]: System.getProperty('java.vendor') == 'Oracle Corporation'
[14:02:33 INFO]: System.getProperty('sun.arch.data.model') == '64'
[14:02:33 INFO]: proxy == DIRECT
[14:02:33 INFO]: JFX is already initialized
[14:02:33 INFO]: Refreshing local version list...
[14:02:33 INFO]: Refreshing remote version list...
[14:02:34 INFO]: Refresh complete.
[14:02:34 INFO]: Loaded 1 profile(s); selected 'Edward_K1'
[14:02:34 INFO]: Refreshing auth...
[14:02:34 INFO]: Logging in with access token
[14:02:37 INFO]: Getting syncinfo for selected version
[14:02:37 INFO]: Queueing library & version downloads
[14:02:38 FATAL]: Unhandled exception in thread Thread[pool-2-thread-2,5,main]
com.google.gson.JsonSyntaxException: duplicate key: null
at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:191) ~[Minecraft.jar:?]
at com.google.gson.internal.bind.MapTypeAdapterFactory$Adapter.read(MapTypeAdapterFactory.java:146) ~[Minecraft.jar:?]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:93) ~[Minecraft.jar:?]
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:172) ~[Minecraft.jar:?]
at com.google.gson.Gson.fromJson(Gson.java:795) ~[Minecraft.jar:?]
at com.google.gson.Gson.fromJson(Gson.java:761) ~[Minecraft.jar:?]
at com.google.gson.Gson.fromJson(Gson.java:710) ~[Minecraft.jar:?]
at com.google.gson.Gson.fromJson(Gson.java:682) ~[Minecraft.jar:?]
at net.minecraft.launcher.updater.RemoteVersionList.getCompleteVersion(RemoteVersionList.java:32) ~[launcher.jar:1.6.89-j]
at net.minecraft.launcher.updater.MinecraftVersionManager.getLatestCompleteVersion(MinecraftVersionManager.java:213) ~[launcher.jar:1.6.89-j]
at net.minecraft.launcher.updater.MinecraftVersionManager.getLatestCompleteVersion(MinecraftVersionManager.java:37) ~[launcher.jar:1.6.89-j]
at com.mojang.launcher.game.runner.AbstractGameRunner.playGame(AbstractGameRunner.java:67) ~[launcher.jar:1.6.89-j]
at net.minecraft.launcher.game.GameLaunchDispatcher$1.run(GameLaunchDispatcher.java:111) ~[launcher.jar:1.6.89-j]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[?:1.8.0_221]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[?:1.8.0_221]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_221]