DS6321 out of range, no power at base

This sounds like a registration problem, the handset(s)
and the base have lost identification with each other.

I. To address this, first de-register the handset(s) ---
do this procedure for each handset:

0. Start by taking off the battery compartment cover....

1. press [menu]
2. scroll up/down to "Settings"
3. enter * 7 8 9 0 #
4. scroll down to "next page", press [select]
5. scroll down to "Register Clear?", press [select]
6. display asks "Confirm?" or "Register Clear??", press [select]
7. display reads "Ok" and chirps, press [ off ]

8. UNPLUG THE HANDSET BATTERY (why the cover was off)

9. Wait ~30 seconds, re-connect the battery & replace the cover

10. display reads "Not Registered" ===============================

II. To register the handset to the base:

1. press [Find Handset] on the base and hold for
~4 sec until the "In Use" lamp lights.
2. press # on the handset and set the handset into
the handset cradle on the base
3. within 30 seconds or so, the handset will either
chirp and display "Handset Registered", then
"Handset #1" or it will say "Registration Failed".

NOTE: the battery must be well charged prior to the
registration process, a weak battery may cause a
"Registration Failed". Charge the battery for a few
hours and try the registration ( II ) again.

NOTE: the base can only handle 5 handsets and will
increment the number of each handset registered
until "Handset #5" has appeared, even if some of
the handsets are lost/not in use. Trying to register
more than 5 handsets will result in "Registration Failed."
===============================

III. To clear the base of all handset registrations and
be able to start registering again at Handset #1:

1. press [Find Handset] on the base and hold past ~4 sec when the "In Use" lamp lights, at
about 10 secs the "In Use" lamp will begin to
blink.
2. release the [Find Handset] button momentarily,
then briefly press it again. After a moment,
all handsets that were registered to the base
(if any) will display "Not Registered" and be
ready for fresh registration
3. for multiple handsets, return to II. above and
register each handset in turn.
===============================
Good luck !!