Hello
Being able to access your phone is definitely important, and I want to be sure you are able to use your service. I would love to help with this.
The emergency only error can be linked to a few things where a network issue is occurring. First, it is always best to check and make sure your SIM card is inserted properly. We have a great online Device Support Tool which provides step by step instructions on how to remove a SIM card properly. Once you are here, you will select the make and model of your device. It will create a personalized screen for your phone. Please select About Device> Insert SIM.
Another thing this can be linked to is no active service and no signal reception. To help pinpoint where the issue is occurring, you can check out our Troubleshoot and Resolve tool. Once you have selected your phone, you will then select your issue. Under Service/network issue, please tap onto Phone Calls. It will walk you through on troubleshooting your device to find the cause.
If these troubleshooting steps do not help, the next best thing would be to replace your SIM card to make sure this is not a device issue. You can get a free SIM card at any AT&T Company store and we can get your device reactivated at no cost.
I hope this information helps you out. Have a great rest of your day!
Vanessa, AT&T Community Specialist