Starting from today i am receiving the following errors on asterisk.. What can be the reason for it? [May 7 11:45:16] ERROR[14885]: chan_dahdi.c:10515 dahdi_pri_error: ACK received for '0' outside of window of '3' to '4', restarting [May 7 11:45:16] WARNING[14885]: chan_dahdi.c:3347 pri_find_dchan: No D-channels available! Using Primary channel 16 as D-channel anyway! [May 7 11:45:16] ERROR[14885]: chan_dahdi.c:10515 dahdi_pri_error: !! Got a UA, but i'm in state 7 [May 7 11:45:42] NOTICE[14885]: chan_dahdi.c:10801 pri_dchannel: PRI got event: HDLC Bad FCS (8) on Primary D-channel of span 1 !! Unknown IE 50 (cs5, Unknown Information Element) [May 7 11:46:24] ERROR[14885]: chan_dahdi.c:10515 dahdi_pri_error: ACK received for '0' outside of window of '2' to '3', restarting [May 7 11:46:24] WARNING[14885]: chan_dahdi.c:3347 pri_find_dchan: No D-channels available! Using Primary channel 16 as D-channel anyway! [May 7 11:46:24] ERROR[14885]: chan_dahdi.c:10515 dahdi_pri_error: !! Got a UA, but i'm in state 7