Apple Watch is not recognising any activity. What is the problem

I have since solved the problem. Something was seemingly corrupted in the iPhone's Health database. Nothing could read or write data to the Health database, including step data (which should be automatically added from the Mwhatever chip) and manually entered data such as weight.

To solve the issue, I unpaired the phone and watch, then set up both the phone and watch as new. Setting up the phone from a backup did not solve the problem because the (hypothesized) corrupt database was (seemingly) included in the backup.

Since setting up the phone as new and re-pairing the watch, Health data works fine.

I love traveling but I have the same problems with my appleWatch.

I contacted the Support, It's a well known problem since the watch have launched. The "Bug" isn't fixed yet.

The Genius told me, the only way to handle that problem is to deactivate the automatic time adjustment of the iPhone and Watch.

Well it's not a satisfying solution but it works. The only problem is that you need to calculate the current time as it won’t display the correct local time.