By default, users can participate in an event as the same participant in different browser windows via their login method.

If it is necessary that only one connection exists per user, this can be set in the session overview.

Open the session settings by clicking on "Edit Event".

Click on "Event Settings" in the navigation bar that opens.

Detailed information on all the individual setting options for "General event settings" can be found here.

Scroll down in the window to the item "Access". 

There you have the option to select or deselect the checkbox "Allow multiple connections" by placing a tick or not.

If the tick is set (default), several parallel connections are allowed for the same participant. This means that participants can take part in the event simultaneously via several devices (e.g. mobile phone, laptop, tablet, etc.).

If the tick is not set, only one connection per participant is allowed. This ensures that existing connections to the event are terminated and the participant is informed of this.