In case someone else with that problem googled and came here:
There is an issue with the extension files for wearable and the current 4.0 emulator image (as per June 2020). webapis is not installed correctly. If you download the wearable extension files, and try to start the emulator, then it is not correctly installed in the emulator image due to a package conflict. Maybe it gets fixed at some point, until then, make sure to download the Samsung wearable extension from package manager. You might get that error message popup. Then you need to delete 3 files in that folder. Also see the GitHub issue for the workaround: https://github.com/Samsung/Tizen.NET/issues/54#issuecomment-640270363
(The needed webapi-plugin-sec is one package of the extensions. When not correct installed on the 4.0 emulator image, it causes the error described above)
Since I had the exact same issue recently and found this thread via google, I decided to update the workaround here in this (old but still current) thread.
Cheers mate