LPC55S69 MQTT example problems

Hello together,

I would like to use MQTT on the LPC55S69-EVK. For this purpose, I have loaded the example "Paho MQTT Example" from the website https://www2.keil.com/iot/lpc55s69-evk . But unfortunately the example does not work for me and I hope someone here can help me.

My approach so far:

- I have installed uVision version 5.34.

- I have unzipped the project on my desktop

- I opened the project by double clicking on the file paho_mqtt_demo.uvprojx

- I selected the option with the ESP8266 via the Batch Set Up and rebuilt it

While building I got the following error message

.\Objects\paho_mqtt_demo.axf: Error: L6218E: Undefined symbol SystemCoreClockUpdate (referred from main.o).
.\Objects\paho_mqtt_demo.axf: Error: L6218E: Undefined symbol SystemCoreClock (referred from clock_config.o).
.\Objects\paho_mqtt_demo.axf: Error: L6218E: Undefined symbol SystemInit (referred from startup_lpc55s69_cm33_core0.o).
Not enough information to list image symbols.
Not enough information to list load addresses in the image map.
Finished: 2 information, 0 warning and 3 error messages.
".\Objects\paho_mqtt_demo.axf" - 3 Error(s), 1 Warning(s).
Target not created.

How can I fix these errors?