Hi: sorry you’re hitting difficulties.
It’s difficult for us to help of course if we can’t see the problem, but is it possible you’ve got a pre-existing CSS rule targeting that table / are you familiar with using your browser’s developer tools and can you track down the cause of this that way?
Perhaps you could try adding something like:
table.tribe-events-calendar { max-width: 900px !important }
To a custom tribe-events.css file (see our Themer’s Guide for details of setting this up) and see if that impacts?