Performed Factory Reset on mr6110 and can not reconnect to my ATT svc.

did you check with att? some need a specific apn programmed in for specific services. 

what made you perform a factory reset? what issues were you experiencing? I would suggest you grab a PDF manual and follow the step by step guide on how to activate your service. the steps would include setting up the correct APN for your carrier as previously suggested. Check also that the SIM card is recognized by the device. Give us specifics of you connectivity problem