I had the same issue, was because my WIFI network was set to WPA2 mixed mode (personal/enterprise), I changed it too WPA2 Personal and it worked fine.
I had the same issue as the above and my WiFi was already set WAP2 personal. I only managed to set my up by using my mobile phone hotspot WiFi access. But, I had slight issues with it saying the WiFi password being wrong, copied the password and when it pasted, it didn’t paste the full password. I therefore shortened the password and then manually type in the password which made it work. Only annoying thing by doing it this way, is I have to refresh the personal hotspot every time I use the scales, as the hotspot switches off when it’s not being used.
FWIW - This was fixed on my network which is running on EERO wifi access points, by disabling IPv6 at the router. Once I rebooted, reset the scale, removed and re-added - everything worked fine. Had the exact same issue with "incorrect wifi" password when it was clearly correct.