This may not exactly be a SmartThings issue, but I have spent hours working with Withings and it is definitely related to SmartThings.
I bought a Withings scale WS-30. It sent data to the cloud for ~20 days.
2-3 days after I installed SmartThings hub it wasn’t connecting.
I have probably exchanged 10-15 emails with Whitings customer service.
I tried every bit of advice (hours) and it would not connect to my router. (Verizon stock wi-fi router)
I returned it and received a new scale which connected for 2 days. Then never again.
I took my scale to work (2 different sites and routers and it works fine).
I have cleared and reset everything incl DHCP router tables, Withings app on phone.
I never was able to get a factory reset to work… probably tried 20+ times.