Root How do I switch carriers

[BlazeNicole]

So, I have the galaxy s5. It is currently unlocked so that it works under the cricket and att network. It is originally a time mobile phone. So, I am switching carriers and I had cricket and I want to use my new to mobile Sim car in the phone. Except my problem is when I put in the Sim card it doesn't work. When I check the apn it says that it's on the top mobile let access point, but when I go to networks it won't let me connect to the tmobile one. It says try again later. What do I do? How do I take the unlock off of this phone. Please help. Thank you.

 

[AZgl1500]

The phone has radio hardware specific to certain carriers and their band plans.

you can change the software, but if the hardware is not compatible, it won't work.

you must stick with a carrier that uses the same band plans as the original phone's carrier used.

 

[EarlyMon]

http://www.willmyphonework.net/

 

[Crashdamage]

Let me see if I understand you...

You have an unlocked S5 that you have been using on Cricket/AT&T. You want to switch to T-Mobile and your S5 is originally a T-Mobile phone, so that should work perferctly. You already have a T-Mobile SIM. But the T-Mobile SIM doesn't work. It won't connect to the T-Mobile network.

Correct so far?

Now questions...
Can you make phone calls? That is, does the phone connect to the basic T-Mobile cellular network for calls but fails to get a data (Internet) connection? Or does it fail to connect at all?

Have you contacted T-Mobile tech support?

It's possible that the phone has been banned on T-Mobile because of unpaid bills. Not saying by you, but maybe a previous owner. This is known commonly as a bad IMEI number. Have you checked into this?