I'm having the same exact issue.

I had same issue - solved it by placing parks and vanilla apartments (dark green residential icon) across the street from it and on each side, then placing a street behind it with parks and vanilla apartments on the side of that street backing the RICO building, then placing fire, police, and clinic within about 1 block of these, then waiting (took about 5 real-time hours) for the apartments to "level up". Then the RICO stopped complaining.
Hope this helps

If you click the land value icon (left column of icons on CS screen) you can see the land value colors. The RICO has to have the dark blue around it (and sometimes a tiny little tinge of the green) before it stops complaining. My previous comment tells you how I got it to change color.