No video calls possible

[Wolf_A]

Hello
I have several echoes, echo show and dot in our house in USA and one echo spot in our apartment in Germany.
I'm really happy with the echoes.
However, no video call works between the Echo Show in the USA and the Echo Spot in Germany.
I can speak, but there is no video. The camera is enabled in both echoes! But there is no camera symbol / icon in the display.
Any Ideas???