I’m glad you got it fixed, and the solution is the same, but it’s not because of the Samsung login.
This issue is covered in the community FAQ on how to use sensors to trigger echo routines.
The short answer is that there is a specific sequence of steps that you must do. Disable the SmartThings skill, log out of the Amazon app, log back into the Amazon app, and re-enable the SmartThings skill. After that you will be able to use your SmartThings sensors in echo routines.