Nextcloud Talk not able to call more than two persons


We have NC 24.0.5, Talk 14.0.5, coturn is installed on separate server, it is defined in NC talk admin settings (with tick). But we are not able to connect more than 2 participants. Some time connect and sometime not. Its observed after upgrade NC from 24.0.5 to 24.0.6. We have also signaling server (HPB), we tried with and without it having same issue.

Please suggest.