Critical Error message

Hi,
I have just bought and downloaded a theme for my website, however when I try and activate it I get this message- “There has been a critical error on this website. Please check your site admin email inbox for instructions.”

I have tried downloading different versions of WordPress but with no success. This is the theme I have bought : Beautiful Floral Watercolor - Blog & Shop by BakerWebDev | ThemeForest
Also it says : “BakerWebDev has chosen not to support this item.” which is really helpful… Could anyone help me with this?

The item support ( if available ) is being provided by the author. For anyone else, it’d be a “work” to solve your problem but it’s hard to say anything before checking the system logs on your server.

Unfortunately, it says that the author doesn’t provide support for this item… I have message the author directly (not responded yet) as I would hope they would be able to help at least update their theme as I believe that might be causing the issue. Thanks for your reply