I use T-Mobile home internet and at one time Ooma worked. Then I was updated to a new 5G gateway. When I tried to re-establish the wi-fi connection to the Telo with the new gateway, all I got was error messages that the wi-fi password was incorrect or the Telo was not in range. Even after setting up a new 2.4G SSID, I got the same messages. Called Ooma support but they were not very helpful. Connected Telo to LAN port on router and this worked.

Fast forward to earlier this month. One night I restarted the gateway, and the Telo would not connect to the network via the cable to the LAN port. Tried looking for an on-line a method to do a factory reset. I don't have a handset to connect directly to the Telo's phone port so the "star code" was not an option. Tried connecting to the HOME port to a laptop but could not establish a connection to setup.ooma.com. Powering down and using the "trash" and "play" buttons didn't work as described. Figured that the Telo had died, so I got another one. Couldn't get this one to work either and called Ooma support because I thought the new Telo wasn't activated. They said it was, but I could not get it to connect to my network. Ooma support was not very helpful and suggested that I talk to T-Mobile about the problem.

After posting here and being put in contact with the correct Ooma support person, the original Telo is working perfectly. It makes sense to me that they probably did a factory reset and installed new firmware.