"emergency calls only" will occassionally display on my alcatel cell phone.At that time I can't make other calls. What is wrong?

Emergency calls only is a symptom where a cellphone loses its registration to a valid network operator. It usually happens to me when I am in another country and the cellphone cannot locate valid operators. Looks like some telcos choose particular network partners. What I do is choose the network operator manually in the phone's setting.

If you are in your home country and this happens, it only tells you that you are out of coverage area and the phone is losing connection to your network operator. Maybe you are inside a building with thick walls which cause poor reception. You may try choosng an area where the symptom goes out.