It is working again!! I hope this will help others as well.I contacted
google support via chat. Later they contacted me by e-mail and they
suggested the following:"In order to fix issues with your Google Home
app unable to link any third-party servic...
Same here on Pixel 6. It suddenly started yesterday morning. For all
services I get the message "Could not reach...". Surprisingly it works
fine on the smartphone of my partner, also a Pixel 6. Very weird and
annoying.