Phone trying to connect to the base but cannot

You possibly have a Mhz signal conflict with another appliance in your home or in another 'apartment' if you live in a complex.  If not, there is a similar or identical signal (with the same Mhz listed on your phone in your home from another appliance trying to use the same frequency) interfering, like a router or router/modem for wireless internet.  I had a similar problem when I had a wireless home phone not connecting to the base and would not call, stay connected or code right with the base.  I used a Linksys router to connect to an AT&T modem and nothing matched. Until I got AT&T to upgrade me to their "2wire" router/modem combination built in and my wireless internet problem was solved.  But, the V-Tech phone lost it's ability to connect or operate properly after that, even with a new battery.  We scrapped the wireless base and phone and now stay wired, also an option.