Cisco 2811 cme does not let you into the audio conference, but there are free places, where to dig?

Question

SIP

Good afternoon, colleagues
It happened to work out the issue of telephony, stuck in place.
- there are 10 seats in the conference, only 4 can connect ( TYPE conf column 1), the rest are not allowed ( after requesting a pin - silence in the phone)
CME#sh dspfarm dsp idle
SLOT DSP VERSION STATUS CHNL USE TYPE RSC_ID BRIDGE_ID PKTS_TXED PKTS_RXED
0 1 32.1. 5 UP N/A FREE v-conf 2 - - -
0 1 32.1.5 UP N/A FREE v-conf 2 - - -
0 1 32.1.5 UP N/A FREE v-conf 2 - - -
0 2 32.1 .5 UP N/A FREE v-conf 2 - - -
0 2 32.1.5 UP N/A FREE v-conf 2 - - -
0 8 32.1.5 UP N/A FREE conf 1 - - -
0 8 32.1.5 UP N/A FREE conf 1 - - -
0 8 32.1.5 UP N/A FREE conf 1 - - -
0 8 32.1.5 UP N/A FREE conf 1 - - -
Total number of DSPFARM DSP channel(s) 9