Hello Mihai,
I checked from hedex, it only allows maximum of 40 concurrent voice calls.
Please refer to the below
Maximum number of registered users
500
Maximum number of registered groups
40
Maximum number of concurrent voice calls
40
Maximum number of concurrent voice transcoding channels
16
Maximum number of concurrent video calls
20
Maximum number of concurrent video transcoding channels
4
Maximum number of concurrent GIS services
500
Maximum number of registered fixed cameras
4
Maximum number of fixed cameras for polling
4
Thank you