Observing that channels are getting stuck in HANGUP state.. So next attempt to make outgoing calls prompts "Channel in use"

freeswitch@mansarover> ftdm core state HANGUP

[s2c1][2:32] in state HANGUP
[s2c2][2:33] in state HANGUP
[s2c3][2:34] in state HANGUP
[s2c4][2:35] in state HANGUP
[s2c5][2:36] in state HANGUP
[s2c6][2:37] in state HANGUP
[s2c7][2:38] in state HANGUP
[s2c8][2:39] in state HANGUP
[s2c9][2:40] in state HANGUP
[s2c10][2:41] in state HANGUP
[s2c11][2:42] in state HANGUP
[s2c12][2:43] in state HANGUP
[s2c13][2:44] in state HANGUP
[s2c14][2:45] in state HANGUP
[s2c15][2:46] in state HANGUP
[s2c17][2:48] in state HANGUP
[s2c18][2:49] in state HANGUP
[s2c19][2:50] in state HANGUP
[s2c20][2:51] in state HANGUP
[s2c21][2:52] in state HANGUP
[s2c22][2:53] in state HANGUP
[s2c23][2:54] in state HANGUP
[s2c24][2:55] in state HANGUP
[s2c25][2:56] in state HANGUP
[s2c27][2:58] in state HANGUP
[s2c28][2:59] in state HANGUP
[s2c29][2:60] in state HANGUP
[s2c30][2:61] in state HANGUP
[s2c31][2:62] in state HANGUP

Total channels in state HANGUP: 29


freeswitch@mansarover> ftdm dump wp2 1

span_id: 2
chan_id: 1
physical_span_id: 2
physical_chan_id: 32
physical_status: ok
physical_status_red: 0
physical_status_yellow: 0
physical_status_rai: 0
physical_status_blue: 0
physical_status_ais: 0
physical_status_general: 0
signaling_status: UP
type: B
state: HANGUP
last_state: TERMINATING
txgain: 0.00
rxgain: 0.00
cid_date:
cid_name:
cid_num: 01203890380
ani:
aniII:
dnis: 09819154202
rdnis:
cause: NORMAL_CLEARING
session: (none)

-- States --                   -- Function --                 -- Location --                 -- Time Offset --
DIALING => PROCEED             [on_proceeding]                [ftmod_libpri.c:1586]          0ms
PROCEED => TERMINATING         [on_hangup]                    [ftmod_libpri.c:1444]          4991ms
TERMINATING => HANGUP          [channel_on_hangup]            [mod_freetdm.c:623]            1ms
HANGUP => HANGUP_COMPLETE      [on_hangup]                    [ftmod_libpri.c:1458]          153ms
HANGUP_COMPLETE => DOWN        [state_advance]                [ftmod_libpri.c:1266]          0ms
DOWN  => DIALING               [channel_outgoing_channel]     [mod_freetdm.c:1767]           757ms
DIALING => PROCEED             [on_proceeding]                [ftmod_libpri.c:1586]          158ms
PROCEED => RINGING             [on_ringing]                   [ftmod_libpri.c:1685]          8029ms
RINGING => TERMINATING         [on_hangup]                    [ftmod_libpri.c:1477]          35432ms
TERMINATING => HANGUP          [channel_on_hangup]            [mod_freetdm.c:623]            0ms

Time since last state change: 1213972ms

freeswitch@mansarover> status
UP 0 years, 0 days, 0 hours, 54 minutes, 5 seconds, 411 milliseconds, 728 microseconds
FreeSWITCH (Version 1.5.15b git acd8d74 2014-10-03 16:48:43Z 64bit) is ready
274 session(s) since startup
1 session(s) - peak 13, last 5min 2
0 session(s) per Sec out of max 30, peak 3, last 5min 3
1000 session(s) max
min idle cpu 0.00/99.83
Current Stack Size/Max 240K/8192K