Most cordless phones will say connecting when the handset is out of range, the base has no power or the base does not have a dial tone.
I start my tests at the base and make sure that another phone (preferably an old corded phone) gets a dial tone at that jack. Try a new phone cord to check if the cable is bad. Check if the power brick for the base is warm and that the outlet has power. For some phones, you can reset them by unplugging the base and removing the battery from the handset. Then reconnect the battery and plug in the base. Check if the handset and base can communicate (try the Find Handset option). If needed re-register the handset.
If the test phone doesn't get a dial tone, then you need to find where you have a wiring problem. Try the test phone at another phone jack. If there is still no dial tone, find the telephone service box (where the phone line comes in). If you have a fairly new service, you will find an RJ-11 jack in the box. Plug in your test phone and check for a dial tone. If you have no dial tone, contact your phone company. They will come and fix the line for free. (If you can't use an RJ-11 cord at the service box, your phone company will test this outside connection.)
If there is a dial tone at the service box or at one jack and not another, it's an inside wiring problem. Look at any open wires (perhaps in the basement) for obvious damage. Open the jack and check for loose wires. (There are two types of jacks - one wraps the wire around a screw, the other requires a punch down tool to secure the conductors in the keystone. The conductors should be connected to the terminals in the correct order. To see a picture of the terminal connections that are used, see http://www.lanshack.com/wire_phone_jack.aspx
. The punchdown tool is available at many home improvement stores in the wiring aisle.)
If your test phone had dial tone at the original jack and resetting the phone by disconnecting the power did not help, then the phone needs service. If it is under warranty, contact V-tech. Otherwise, you may be better off replacing the unit. These phones are not meant to be user serviced.
I hope this helps.
(if you add a comment with the model, then I will check if I can provide more details in my solution.)