Because Unity 5.x doesn't support Android arm64 binaries, when using the Unity SDK, the following build error may occur.
Found plugins with same names and architectures, Assets/Plugins/Android/libs/arm64-v8a/libSmartBeatNdk.so (ARMv7) and Assets/Plugins/Android/libs/armeabi-v7a/libSmartBeatNdk.so (ARMv7). Assign different architectures or delete the duplicate.
If this error occurs, delete the folder shown below and rebuild the project.
<Project folder>/Assets/Plugins/Android/libs/arm64-v8a