There has been significant coverage of the topic of connecting your Aria (Aria 1) to a new network. For some of us, none of the posted solutions work. Even if the new network supports 11b and has compatibility mode, in some cases it just won't connect. The following solution isn't the cheapest but it generally will work.
The problem seems to be a combination of very old network technology in the Aria, not aligning with that in the newer routers. I for example installed a ASUS zenwifi mesh with intelligent 2.4/5 ghz routing and wifi 6. None of the existing solution seemed to help. However, these scales previously worked just fine with my ASUS AC1900 (AC68U). In my case, I just got an AC1900 router and connected it to my network and set it up so that the scales (I have two of them) connected to the AC1900 instead of my zenwifi. It's not quite a simple as it sounds, but it isn't all that difficult if you are comfortable poking around in the firmware of your router.
Although my example works on ASUS, it should work on other brands as well
1. Acquire an AC1900 (AC68U) (they are old enough to have been around before the Aria was built, but still good enough to be found fairly cheaply in your local computer store.) I'll call it the "old router" below
2. Connect a wan (yellow) port on the old router to your laptop via an ethernet cable.
3. In a browser, connect to the old router from your laptop - likely on 192.168.1.1 (you may need to turn off wifi on the laptop to force the laptop to use the ethernet port)
4. Change the subnet on the old router to make sure it is different than the subnet on your current (new) router. For example, if your new router uses 192.169.1.xxx, then maybe try 192.168.100.1 as the new router subnet.
While you are in here, change the access control to allow control over WAN (you will likely store this router away in a closet and you don't want to have to pull it out and attach an ethernet cable to it when ever you make changes to it) - this will let you access it via your main network (i.e. from the new router hosted network)
5. Create a new network name in the old router - it must be different than your new router network name. For example, the network on the old router might be "old network 2.4" . If you will only use the this old router for the Aria, you could even turn the 5ghz network off (although you might find other old devices that won't connect to your new network so this could help them as well). Setup a password for this old network (for security purposes make it different than the new routers passwords) . Aria likes the security to be WAP Personal.
6. Connect the lan (blue) port on the back of the old router, to a wan (yellow) port on your new router (or to your switch if you are running one). Power cycle the old router. It should now access the internet through your new router. (If you look at the client list on your new router, you should see the old router - although the Aria's you connect later will not be visible on the new router client list)
7. Connect your laptop (via wifi) to the old router (connect to network "old network 2.4"). It should have internet access so you can now go to the scale setup page (fitbit.com/scale/setup). Go through the usual process of setting up the scale (as documented on that web page).
8. Assuming everything works (and this solution should always work), pour a drink and sit back. You just extended the life of your Aria!
9. (optional) Go back into the setup page for the old router (remember above where you set up administration via wan access - you can learn how that works now). Once in the admin - I'd turn off the SSID broadcast for the old network. The scales will still connect to the old router just fine - but you won't see the network name being broadcast around (so less chance for hackers to try and break in via this old network and less confusing when you have guests over and they want to connect to your network)
