Can't compile Cocos2d-x Game for Android because of Admob Plugin

Question

I made a game with cocos2d-x and it runs without any problems on iOS, I have already released it on the App Store. But somehow it doesn't work on Android, i tried compiling it wtih the command "cocos compile -s ~/path/to/game/ -p android" but I get the following error:

/Users/lukas/Documents/CocosGame/Classes/AppDelegate.cpp:27:10: fatal error: 'PluginAdMob/PluginAdMob.h' file not found
#include "PluginAdMob/PluginAdMob.h"
^~~~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated. ninja: build stopped: subcommand failed.

I defined the build type in the gradle properties as: "PROP_BUILD_TYPE=ndk-build". In Android.mk i correctly inlcude all my plugins, it looks like this:

    LOCAL_PATH := $(call my-dir)

    include $(CLEAR_VARS)

    LOCAL_MODULE := MyGame_shared

    LOCAL_MODULE_FILENAME := libMyGame

    LOCAL_SRC_FILES := \
    $(LOCAL_PATH)/../../../Classes/AppDelegate.cpp \
    # $(LOCAL_PATH)/hellocpp/main.cpp \
    $(LOCAL_PATH)/../../../Classes/MenuScene.cpp \
    all classes...

    LOCAL_CPPFLAGS := -DSDKBOX_ENABLED \
    -DSDKBOX_COCOS_CREATOR
    LOCAL_LDLIBS := -landroid \
    -llog
    LOCAL_C_INCLUDES := $(LOCAL_PATH)/../../../Classes

    # _COCOS_HEADER_ANDROID_BEGIN
    # _COCOS_HEADER_ANDROID_END

    LOCAL_WHOLE_STATIC_LIBRARIES += sdkbox
    LOCAL_WHOLE_STATIC_LIBRARIES += PluginSdkboxAds
    LOCAL_WHOLE_STATIC_LIBRARIES += PluginAdMob
    LOCAL_WHOLE_STATIC_LIBRARIES += PluginShare
    LOCAL_WHOLE_STATIC_LIBRARIES += PluginSdkboxPlay

    LOCAL_STATIC_LIBRARIES := cc_static

    # _COCOS_LIB_ANDROID_BEGIN
    # _COCOS_LIB_ANDROID_END

    include $(BUILD_SHARED_LIBRARY)
    $(call import-add-path, $(LOCAL_PATH))

    $(call import-module, cocos)
    $(call import-module, ./sdkbox)
    $(call import-module, ./PluginSdkboxAds)
    $(call import-module, ./PluginAdmob)
    $(call import-module, ./PluginShare)
    $(call import-module, ./PluginSdkboxPlay)

    # _COCOS_LIB_IMPORT_ANDROID_BEGIN
    # _COCOS_LIB_IMPORT_ANDROID_END

How can I fix this error? I tried to find a solution for a few hours now but nothing works for me...