I went into the profile for michaelcrook.org. It says the Universal SSL is activated, but it doesn’t appear to be. Therefore, my site is generating unsecured site messages for people trying to visit.
ETA: Firefox is generating an unsecure error, but Edge says it’s secure. It seems the other browsers say it’s secure, but Firefox on Android says it’s secure. Not sure what to do about this. People are probably clicking away if they’re accessing via Firefox.