Index S2 Smart Scale will not connect to phone after successful set up

Yes, exactly the same here. I found out that even if it is connected to the WiFi router, it cannot send/receive any data. And yes, despite the app keeps saying that it was set up successfully, it can't connect to the internet, nor to the app via BT (so you cannot change the WiFi settings afterwards). I have tried to unpair, reset, reconnect several times with the same results.

Same issue here. Setup works fine and it seems like to scale is connected. However it tries to download a system update, when a red X appears and it shuts down. When I try to measure my weight, same thing happens (and my user does not appear). Have tried contacting the Garmin support without any success and managed to replace the scale with a new one through my retailer. Received the new one today and the same thing happens. Can't find any information on how to solve this.... 

I found, that I can only connect the Scale successfully via hotspot created on my phone. However, this solution is not very convenient. I can connect the Scale to WiFi router, but it is unable to send/receive data. I think, that it just can't communicate with some WiFi routers, mine is HUAWEI HG8245W5. What is yours?

Haven't tried to connect the scale to my phone, but will do to at least to experience how the scale should be working. I have further found that the scale can only connect to 2,4 GHz networks (as tarmbruster described) as it appears in the list of connected devices when browsing through my router settings. The router provides both a 2,4 GHz and a 5 GHz network.

Hence, as you experience as well, the scale connects to my router but is unable to send and receive data - for some unknown reason.

When speaking to Garmin Support they told me it might have to do with the encryption method and suggested to me that I should switch from WPA2-PSK to WPA2, but when speaking to my internet provider they informed me that the two are the same. I have since tried to reach Garmin Support yet again, but with no luck so far. 

My router is an internet provider-specific model from Sagemcom, called WiFi Hub C1.

Did you every find a solution?  I have had my scale for a couple years...no problem.  Had to switch to the HG8245W5 router and cannot get scale to connect!

No, I haven't found any other solution except to connect the scale via mobile hotspot. I have tried several different router settings (and everything what was recommended), without a success. I'm thinking about changing the router or returning the scale (any other device works with that router well).