Is the battery in the cordless phone charged?

Is the base unit plugged in?

Does the base unit's plug work?

Check to see if the phone cord is plugged into the base unit and or to the telephone wall plug.

then turn it back on. I find that sort of thing often works.

so, i guess it aint me.im glad i can still dial out .

...unplugging it, and reversing.
Sometimes the phone has to go full dead to correct these glitches.

The buzz is an indication of trouble on the line. It could be in your wiring or in the telco's cable. The cordless phone is electronic and is probably more sensitive to the line issue, not allowing you to call out. It might work if you switch it from touch tone to dial pulse.

The buzz may be causing the tone receiver in the central office from recognizing them. Dial pulse is basically a make or break of the DC. It is always available on landlines.

A critter could've chewed on the line or something else could have happened to it. Just a thought from a non=tech expert!