ADuM1251 shows no reaction

Hello,

in my project i'm working with an ADuM1251.

Following picture shows my setup.

The microcontroller is connected on PIN 2 and PIN 3. On PIN 6 and 7 four I²C Slave-Devices are connected.

If i start my demo program, i monitoring the signals on PIN 2 and 3. I see the clock and the data, but i dont get an ACK from my slave device. I can not even see the data and clock signals on PIN 6 and 7.

Thus my question, is my setup so far okay?

If it is okay, is the ADuM1251 broken? I measured the Resistor R9 and the Ohmmeter shows ~620Ohm. At all other Resistors the value is ~4k7Ohm.

Thanks for your help.

NiklasM