There are a few cases where one may hear an audible message when trying to monitor a team member's call, such as "Sorry, you cannot monitor this call", which include the following possibilities:
A Truly admin may have implemented role-based permissions preventing team members in certain roles from being monitored.
The call displayed may have recently ended, or the team member may have used the Voicemail Drop feature to leave a voicemail and end the call.
The team member may be located in a different region. (Your region is defined by your network location or the connection being given to Truly by your VPN connection)
A local network, VPN, proxy, or DNS server issue may be interfering with in-region monitoring.
If you have any questions or issues, please reach out to the Truly support team at support@truly.co or by clicking your initials in the upper right corner in the desktop app and we'll be happy to assist!