Plugin is blocking possibility to comment

A visitor reported to me that she wasn’t able to comment on my latest blog. After checking it, I found out that a comment on ANY of my blogs resulted in a 500-error.

My host found ‘something’ in antispambee was causing this.
On his suggestion I deactivated the plugin and yes, I could comment again.

But I love antispambee and how it has been helping me for years now!
So I don’t want to have to switch to another comment spam ‘defender’.

I hope you can help me resolve this problem – thanks! ??

Regards, Renée

Browser: error occurs in any browser
Operating system: Windows 10
Theme: FocusBlog (ThriveThemes)
WP version: 4.9.8

Let me know please if you need additional technical details

The page I need help with: [log in to see the link]