Every time I want to play the 18w15a snapshot crash. What I have to do to Minecraft work?

Details:
*The game crashed whilst initializing game
Error: java.lang.IllegalStateException: Not a JSON Object: null

Crash report:
---- Minecraft Crash Report -------- Minecraft Crash Report ----// I let you down. Sorry
Time: 15/04/18 12:13Description: Initializing game
java.lang.IllegalStateException: Not a JSON Object: null at com.google.gson.JsonElement.getAsJsonObject(JsonElement.java:90) at tl.a(SourceFile:72) at tl.a(SourceFile:65) at ud.a(SourceFile:35) at ty.a(SourceFile:38) at ua.a(SourceFile:32) at cas.a(SourceFile:1189) at cap.an(SourceFile:440) at cap.a(SourceFile:369) at net.minecraft.client.main.Main.main(SourceFile:141)

A detailed walkthrough of the error, its code path and all known details is as follows:---------------------------------------------------------------------------------------
– Head --Thread: Client threadStacktrace: at com.google.gson.JsonElement.getAsJsonObject(JsonElement.java:90) at tl.a(SourceFile:72) at tl.a(SourceFile:65) at ud.a(SourceFile:35) at ty.a(SourceFile:38) at ua.a(SourceFile:32) at cas.a(SourceFile:1189) at cap.an(SourceFile:440)
– Initialization --Details:Stacktrace: at cap.a(SourceFile:369) at net.minecraft.client.main.Main.main(SourceFile:141)
– System Details --Details: Minecraft Version: 18w15a Operating System: Windows 7 (amd64) version 6.1 Java Version: 1.8.0_25, Oracle Corporation Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation Memory: 149821496 bytes (142 MB) / 268435456 bytes (256 MB) up to 1073741824 bytes (1024 MB) JVM Flags: 8 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx1G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=16M Launched Version: 18w15a LWJGL: 3.1.2 build 29 OpenGL: Intel(R) HD Graphics 4000 GL version 4.0.0 - Build 10.18.10.4303, Intel GL Caps: Using GL 1.3 multitexturing.Using GL 1.3 texture combiners.Using framebuffer objects because OpenGL 3.0 is supported and separate blending is supported.Shaders are available because OpenGL 2.1 is supported.VBOs are available because OpenGL 1.5 is supported.
Using VBOs: Yes Is Modded: Probably not. Jar signature remains and client brand is untouched. Type: Client (map_client.txt) Resource Packs: Current Language: ~_ERROR~ NullPointerException: null Profiler Position: N/A (disabled)