What does the message "Too few services" mean?

After some testing myself, I discovered this message means your industries are lacking one or more of your basic services such as fire protection, police, mass transit, etc. Placing offices near polluting industries can cause the "Too few services" message because of low land value. What the message actually is saying is: there is something undesirable about coverage or the location. In my case it was fire:

This was my fire coverage before I added a fire station.

And this is after. The messages all disappeared within a few seconds. If you are getting this message, be sure to check all your overlays to see what they are lacking!