Invalid Sim/Sim Failure Iphone 4s Unlocked T-mobile

[chen04]

I keep getting an Sim Failure/Invalid Sim after a few days using my iphone 4s. If I power on/off it starts working normally again, but the problem is reoccuring. I did trim the sim using a sim cutter, do I need to goto the t-mobile store and get a micro sim? Any help is appreciated.

Thanks,
Brian

 

[Applejuiced]

Might be a bad sim or maybe its not sitting right in the tray.

 

[chen04]

Might be a bad sim or maybe its not sitting right in the tray.

It works when I power on/off the phone. Is it still the sim? Bad iphone?