For this type of problem, you need to isolate the issue. It could be the phone, the inside wiring, or the outside wiring. I like to use an old rotary phone for testing but any basic corded phone should work. Get a new RJ-11 phone cable as well.
Unplug the base unit and plug in the test phone to that jack. Check if you get a dial tone. (Try a new cable if the initial one doesn't work.) If your test phone has a dial tone, then the problem is isolated to the cordless phone. (If the test phone works with the new cable, do check if Uniden works with that cable.) Modern phones are not designed to be fixed by the consumer. If the phone is under warranty, contact Uniden Customer Service. (Otherwise decide if the costs are worthwhile for you; there will be a significant delay before the phone is returned/replaced.)
If you do not get the dial tone, you need to track down the wiring issue. Next move to another jack on the phone line and check if there is a dial tone on your test phone. If there is a dial tone, you have isolated the problem to the jack or the wiring to the jack.
If there is still no dial tone, find where your telephone service comes in to your building. If you can, open the box. Determine the type of connection used there. If you are lucky, you will find a RJ-11 jack for your phone line. Plug in your test phone and check for a dial tone. If there is no dial tone, contact your telephone provider. They will fix this outside problem for free.
If the connection is not a RJ-11 jack, you will need to call the telephone company so that they can determine if the problem is inside or outside.
If you do have a dial tone, then the problem is with the inside wiring. Inspect the visible wires for damage. Open the faceplates for the jacks and check for loose wires. There are two types of connectors. Screw type connectors need the wire stripped back a little then wrap around the screw and tighten. The other type is a punchdown jack. To repair a loose wire in this, you will need a punchdown tool. These are often available in hardware/home improvement stores in the wiring section. http://www.lanshack.com/wire_phone_jack.aspx
has clear pictures of the wire color to pin pattern.
You may want a professional to check the wires inside the walls. Your telephone provider will do this for a fee.
I hope this helps.