All Gradle commands don't seem to work

[Reflxction]

Hello. Over the past days, I've been encountering issues with Gradle that Forge uses. Every Gradle command I execute seems to fail with the same error. I haven't modified my build.gradle or any Gradle file that the workspace contains. I'm getting the following errors (this one was on gradlew build):

* Where:
Build file 'my mod workspace\build.gradle
' line: 39

* What went wrong:
A problem occurred evaluating root project 'my mod name'.
> java.lang.NullPointerException (no error message)

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug
option to get more log output.

BUILD FAILED

Total time: 37.669 secs

It says line 39 in build.gradle, which is 

mappings = "stable_20

I'm using Forge 1.8.9

 

Before, everything was running completely fine and I didn't encounter any problems. One of the things I have done was update Java and IntelliJ IDEA. Could that be the cause? If so do I need to update other things like Gradle or will I have to downgrade Java? If not, got any idea or any way to fix that issue? Thanks in advanced.

[Draco18s]

1 hour ago, Reflxction said:

mappings = "stable_20

 

mappings = "stable_20"

 

Maybe?

[Reflxction]

11 hours ago, Draco18s said:

mappings = "stable_20"

 

Maybe?

I think this was a mistake when I copied it, but it was closed with the quotations. 

I sometimes get those:

Etag download for http://export.mcpbot.bspk.rs/versions.json failed with code 40
3

FAILURE: Build failed with an exception.

* Where:
Build file 'my workspace\build.gradle
' line: 39

* What went wrong:
A problem occurred evaluating root project 'Impurity Capes'.
> java.lang.NullPointerException (no error message)

"failed with code 403" means forbidden access, but I could access this from my browser and even tried a VPN.

Edited July 3, 2018 by Reflxction