I bought a used Samsung SM-G550T phone for use with my IP cameras. It has a T-Mobil simm card but no service.I don't want the service. My question is I would like to be able for it to connect to my wifi so I could use it for calls or txt from home. No matter what I do it comes up with the error Under (More connection settings- Wi-Fi Calling) ER101 invalid Certificate. From what I've read on the internet it should be able to do this. Am I missing something or this phone will not do this. Also I can go on the internet with it. And if I take out the simm card then it says no simm card installed.
Thank you for any help you can offer
Thank you for any help you can offer