Sometimes UnityHub can’t download Android SDK & NDK, then you maybe face the following messages:
The server is currently unresponsive.
Installation Failed, something went wrong installing modules for Unity.
Unity will indicate the specific NDK version you need.
Ex. Unity 2019.4.13f1 => NDK 19.0.5232133
But you might only found the latest of the main version of NDK.
Ex. NDK 19.2.5345600
https://developer.android.com/ndk/downloads/older_releases
1. Hack the NDK version number
Open file source.properties with a txt file
Modify Pkg.Revision to your NDK target version number
Pkg.Revision = 19.0.5232133
2. Fix NDK Signing
Open terminal, go to NDK root and execute the following scripts.
echo "Resetting Extended Attributes" sudo xattr -cr toolchains/llvm/prebuilt/darwin-x86_64/bin/clang sudo xattr -cr toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ sudo xattr -cr toolchains/llvm/prebuilt/darwin-x86_64/lib64/libc++.dylib sudo xattr -cr toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/arm-linux-androideabi/bin/ld.bfd sudo xattr -cr toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/arm-linux-androideabi/bin/ld.gold sudo xattr -cr toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-objcopy sudo xattr -cr toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-strip sudo xattr -cr toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/aarch64-linux-android/bin/ld.bfd sudo xattr -cr toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/aarch64-linux-android/bin/ld.gold sudo xattr -cr toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/bin/aarch64-linux-android-objcopy sudo xattr -cr toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/bin/aarch64-linux-android-strip sudo xattr -cr toolchains/x86-4.9/prebuilt/darwin-x86_64/i686-linux-android/bin/ld.bfd sudo xattr -cr toolchains/x86-4.9/prebuilt/darwin-x86_64/i686-linux-android/bin/ld.gold sudo xattr -cr toolchains/x86-4.9/prebuilt/darwin-x86_64/bin/i686-linux-android-objcopy sudo xattr -cr toolchains/x86-4.9/prebuilt/darwin-x86_64/bin/i686-linux-android-strip sudo xattr -cr toolchains/x86_64-4.9/prebuilt/darwin-x86_64/bin/x86_64-linux-android-objcopy sudo xattr -cr toolchains/x86_64-4.9/prebuilt/darwin-x86_64/bin/x86_64-linux-android-strip echo "Fixing NDK Signing" sudo codesign --force --deep --sign - toolchains/llvm/prebuilt/darwin-x86_64/bin/clang sudo codesign --force --deep --sign - toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ sudo codesign --force --deep --sign - toolchains/llvm/prebuilt/darwin-x86_64/lib64/libc++.dylib sudo codesign --force --deep --sign - toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/arm-linux-androideabi/bin/ld.bfd sudo codesign --force --deep --sign - toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/arm-linux-androideabi/bin/ld.gold sudo codesign --force --deep --sign - toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-objcopy sudo codesign --force --deep --sign - toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-strip sudo codesign --force --deep --sign - toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/aarch64-linux-android/bin/ld.bfd sudo codesign --force --deep --sign - toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/aarch64-linux-android/bin/ld.gold sudo codesign --force --deep --sign - toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/bin/aarch64-linux-android-objcopy sudo codesign --force --deep --sign - toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/bin/aarch64-linux-android-strip sudo codesign --force --deep --sign - toolchains/x86-4.9/prebuilt/darwin-x86_64/i686-linux-android/bin/ld.bfd sudo codesign --force --deep --sign - toolchains/x86-4.9/prebuilt/darwin-x86_64/i686-linux-android/bin/ld.gold sudo codesign --force --deep --sign - toolchains/x86-4.9/prebuilt/darwin-x86_64/bin/i686-linux-android-objcopy sudo codesign --force --deep --sign - toolchains/x86-4.9/prebuilt/darwin-x86_64/bin/i686-linux-android-strip sudo codesign --force --deep --sign - toolchains/x86_64-4.9/prebuilt/darwin-x86_64/bin/x86_64-linux-android-objcopy sudo codesign --force --deep --sign - toolchains/x86_64-4.9/prebuilt/darwin-x86_64/bin/x86_64-linux-android-stripReferences
https://issuetracker.unity3d.com/issues/unity-hub-android-ndk-integrated-ndk-version-is-not-compatible-with-available-unity-hub-or-android-developer-ndk-versions
https://forum.unity.com/threads/cant-android-il2cpp-build-on-macos-catalina.726803/