xFi Advanced Security is blocking my company's website

One of my company's product domains is being blocked by xFi Advanced Security.

https://v2.hostfully.com is the subdomain that serves our guidebook platform, and it works fine when i have this featured disabled, but when i turn on xFi Advanced Security, I get a message (different depending on the browser) about not being able to load the page because a secure connection cannot be established.

Can this be investigated to find out why?    I had a similar issue about 4 months ago with Xfinity's "Protected Browsing" which was (at least then) powered by the categorization database at https://tools.zvelo.com/

fixing our negative categorization there resolved the issue, but now a few months later the issue reappears even though Zvelo still shows our site as safe (as does every other categorization site i can find)

anyway,  any help to point me in the right direction would be useful.   At the moment i just tell any customers that report this to turn off this feature in xFi because it's buggy, but i'd like to solve the root cause.