Depending on your role during an event on VoiceBoxer (i.e. moderator, presenter, interpreter, audience) you have different possibilities regarding the choice of browser.
Firefox can be used until version 68.0, unfortunately, the latter versions are known to have a bug causing problems receiving audio/video properly and thus affects VoiceBoxer and other similar communication tools.
Microsoft Edge and Safari (from version 12.1) are also among the supported browsers with some limitations. As shown below: video streaming is not available when using Edge, only audio and Safari is fully supported for Moderators and Presenters; Interpreters have only audio and there is no Audience support for now.