Before inviting External guests to present in a Teams Live Event, you must read the following attachment.
NB: Make sure that their external email address is added to Teams Site. This will initiate their email account within our Teams Tenant. The external guest must accept the invite for the process to be complete. Also make sure that the external guest will have downloaded a desktop version of Teams that is not logged into any other clients e.g RBWM, Wokingham, Bracknell (Otherwise their account within these organisations will override the invitation)
Before you can set up a Teams Live Event, you will need to raise a Service Request to have this enabled on your Teams account. Justification is required on Why you need this and provide reasons.
NB: In order to enable Teams Live Events, it can take up to 48 hours to be activated. You will need to account for this time lapse with your request and with planning and testing your event.