Arduino UNO with datalogger shield hangs executing rtc.begin

Hello,

Maybe I posted this in the wrong place, please tell me if so and I will repost if needed.

I have an AZDelivery datalogger shield for my genuine Arduino UNO.
The datalogger shield has a SD card that works fine with the Arduino code examples.
But it also has a RTC (DS1307) on it that I cannot get working.

In the IDE I have installed the "RTClib by Adafruit v2.1.1".
Then when I try the code example "ds1307" it does not work.
With some extra println' s for debugging I found out that it hangs on executing rtc.begin
It does not return any value, it simply hangs there.

What do I do wrong? Why does it hang on executing rtc.begin and how can I fix it?

I believe that the DS1307 is an I2C device. Have you run an I2C scanner to see if it is detected?