I finnaly got my Galaxy S6 edge to work with my Gear Fit R350
I am using the firmware ver. R350XXU0BOA2 which I installed with ODIN. But that did not fix the problem. The bluetooth would stay not connected.
I sent by email (from my computer) the older version of GEAR FIT MANAGER , and downloaded the file from GMAIL on my phone.
I enabled UNKOWN SOURCES on galaxy S6 edge, which can be found on SETTINGS / LOCK SCREEN AND SECURITY , so the phone would allow me to install the .apk file (older version of GEAR FIT MANAGER) file name is: GearFitManager_OA2_1.116.0227_user.apk
Once I installed it, it worked fine.
The only problem is that a few times a day it asks me if I want to update GEAR FIT MANAGER, and I accidentally hit ok. After that, I had to uninstall the updated gear fit manager, and reinstalll the older version again.