Pro Site plugin crashes website when activating - Help!

Whenever I network activate my Pro Sites plugin, my site crashes and I get the Internal Server Error message.
I have to use FTP to delete the Pro Sites folder from my wp-content directory and then the site will start working again.
I have just upgraded to the latest version and it is still happening.
I had been using Pro Sites for a few years without any issues. This problem started occurring after I moved my domain to another VPS (Bluehost). I suspected it might be a resource issue, but I believe I have enough RAM available on the VPS.
I would appreciate any help given from the experts here on how to get Pro Sites working again on my site.
I have granted support access for my site. Thank you.