ESP8266 Json + RGB

Hey Guys,

i have an ESP8266 and want to use i for an analog rgb led strip. I want to use this project https://github.com/corbanmailloux/esp-mqtt-rgb-led. I already set up the Configuration.yaml but i cant compile the esp8266 file. I get this error :

mqtt_esp8266_brightness.ino.cpp.o:(.text._ZN11ArduinoJson9JsonArray7invalidEv[_ZN11ArduinoJson9JsonArray7invalidEv]+0x8): undefined reference to `__cxa_guard_acquire’

mqtt_esp8266_brightness.ino.cpp.o:(.text._ZN11ArduinoJson9JsonArray7invalidEv[_ZN11ArduinoJson9JsonArray7invalidEv]+0xc): undefined reference to `__cxa_guard_release’

mqtt_esp8266_brightness.ino.cpp.o: In function `ArduinoJson::JsonArray::invalid()’:

mqtt_esp8266_brightness.ino:407: undefined reference to `__cxa_guard_acquire’

mqtt_esp8266_brightness.ino:407: undefined reference to `__cxa_guard_release’

mqtt_esp8266_brightness.ino.cpp.o: In function `ArduinoJson::JsonObject::invalid()’:

mqtt_esp8266_brightness.ino:407: undefined reference to `__cxa_guard_acquire’

mqtt_esp8266_brightness.ino:407: undefined reference to `__cxa_guard_release’

collect2.exe: error: ld returned 1 exit status

exit status 1

The ArduinoJson library is already installed.

Can someone please help me?