I'm having the same problem. Since a watch update in August, the "find my phone" feature has stopped consistently working. It will work about 60% of the time. When it doesn't, I receive the error message shown above even though my watch is connected to my phone via bluetooth. I've restarted my phone and watch numerous times but it doesn't seem to affect the consistency of it working. It also doesn't seem to matter whether I'm at my house or not. There also have been no changes to my router. This is a feature I use considerably and need to get it fixed. What can I do?
Thank you for reaching out. I certainly understand your concern with your watch not being able to locate your phone and would be happy to look into this further for you. I would first recommend clearing the cache and data on your Samsung SmartThings app. Please know this may require you to sign back into your Samsung Account on the SmartThings app.
The next step would be to unistnall and re-install the Samsung SmartThing and Wearables app. Please know this will reset your watch.
If you have tried the troubleshooting provided above and are still experiencing these symptoms, I would recommend submitting an error report. Please use this link to properly submit and error report: https://us.community.samsung.com/t5/Samsung-Apps-and-Services/How-to-submit-an-error-report/td-p/247...
I would also recommend contacting our Samsung Customer service team directly at 1-800-726-7864 as this will allow them to remote into your device and verify all setting on your watch.