Check permissions in the intended channel
The person inviting the bot needs the appropriate server permissions. The bot must be able to access the relevant text channel, connect to the voice channel and speak. Channel-specific permission overrides can prevent a session even when the initial server invitation succeeded.
Separate the administrator from the people speaking
Managing a server and holding translation rights are different things. Individual plans cover the subscriber’s voice. Server covers the voice channel according to its configured access. Test with the actual participants and use !status and !languages to check access, usage and available languages.