There have been occasions where a website's design or code causes the Livestream iFrame code to resize improperly.
To fix this, you can make the player responsive by replacing the player width and height to zero.
For example, this is a default iFrame code for the live player embed:
Change the first "560px" and "315px" to zero, as shown below:
The player will now be responsive and should fit within your page's design.