What browser are you using? Have you tried using a different browser?
When you try to edit the page how are you doing it? Are you going through your Dashboard -> Pages -> Edit Page -> Launch Beaver Builder? Or are going to that page and launching Beaver Builder from the Admin Toolbar at the top of the page? If you did it one way try the other way.
Is JavaScript enabled in your browser? Make sure it is turned on
Does the URL after trying to launch beaver builder look like this (specifically the ending)? www.yourwebsite.com/page/?fl_builder
You said you tried &safemode so did it end up looking like this? www.yourwebsite.com/page/?fl_builder&safemode
If you have tried all of these I would suggest making a backup of everything if possible, then uninstalling Beaver Builder and reinstalling it on your site.