Does this bug also affect IX 9.1.1? Logs from one of our IX units today after a report of dial failures:
2020-11-23 22:54:47: INFO Local user dialing [removed].[removed]@[removed].webex.com
2020-11-23 22:54:50: INFO Main Video negotiated Frame Rate is 30fps.
2020-11-23 22:54:50: INFO Connected to [removed].[removed]
2020-11-23 22:54:51: INFO Negotiated Media Configuration: LTRP: Disabled GDR: Enabled High Profile: Disabled Cabac: Disabled
2020-11-23 22:54:51: INFO Endpoint used protocol MUX version 8 for this call
2020-11-23 22:54:51: INFO The presentation has been negotiated to 30 & 5 FPS
2020-11-23 22:54:52: INFO BFCP Status: Negotiated
2020-11-23 22:54:52: INFO Active Control Status: Disabled
2020-11-23 22:55:00: INFO Audio DSCP Current Marking: [BE], Previous Marking: [BE]
2020-11-23 22:55:00: INFO Audio COS Current Priority: , Previous Priority: 
2020-11-23 22:55:00: INFO Video DSCP Current Marking: [BE], Previous Marking: [BE]
2020-11-23 22:55:00: INFO Video COS Current Priority: , Previous Priority: 
2020-11-23 22:55:02: ERROR Call ended due to bandwidth renegotiation timeout (remote DN: [removed].[removed])
I am facing this issue as well, calls traversing the video mesh servers are not going further after few second it gets disconnected.
from the IX5000 unit I see in the logs
Looking into the IX5000 logs I can see that there is a renegotiation of bandwidth for audio and video towards the CUCM as per below:
2021-09-13 13:54:14.909 [CTRL] [INFO] [tid 27985] ReNegoNewBandwidth: added security overhead for AV: new_video_offer_br=12600000, new_audio_offer_br=281600
2021-09-13 13:54:14.909 [CTRL] [INFO] [tid 27985] ReNegoNewBandwidth: rmtTPTopo=3, local_video_bw_single=4000000 negotiated_video_bw_single=4000000 new_video_offer_br=12Fabiano20217000
2021-09-13 13:54:14.909 [CTRL] [INFO] [tid 27985] ReNegoNewBandwidth: started bw_nego_timer for 10 secs
Then the SIP bye message is due to timeout or no response on this bandwidth renegotiation.
2021-09-13 13:54:24.973 [CTRL] [ERR ] [tid 28349] BwNegoTimeOutCallback: enter, bw_nego_timer timed out, disconnect the call
Before the bye message from the IX5000 this device is sending notify and update messages to call manager I believe asking for renegotiation of Bandwidth but this doesn’t happen.
I am wondering if this is something call manager can manage to respond to this bandwidth renegotiation because I don’t see forward this messages to the video mesh servers in order to adjust the bandwidth or there is some misconfiguration.
At the end the call is disconnected from the IX5000 with this error.
2021-09-07 11:49:48: ERROR Call ended due to bandwidth renegotiation timeout (remote DN: 1313499950)
We have set the local Region configuration in call manager and Region towards video mesh server to 32000 Kbps to have enough.
did you get any resolution for this issue?