A critical error has occurred on your website.

I recently bought the plugin as I had a great time trying out the demo.
I did not have any problems with the demo, I did all my tests before purchasing.
Once I had inserted the purchased plugin, a critical error only appeared on the product page. I enclose a photo and post the link to better understand the error.

https://www.joniopesca.com/negozio/mercatino/prova3/

Is there any solution to this problem?
I am waiting for some answers as soon as possible.
Thank you in advance