Trying to activate the "Call Protect" feature

I'm attempting to activate the "Call Protect" feature to put a stop to the frequent spam calls from "unavailable caller". However, when I try to activate the feature on the designated page, I encounter a purple error message that reads "JSP Processing Failure, HTTP code 500". The page freezes as a result.

Can someone confirm if this feature actually works? It's worth noting that we use a VoIP phone.