JUST FIGURED IT OUT!!!
This is caused by one of your roads that is connecting your services (water, power, etc) is not attached!!
You can have all the services in the world, but if there is a tiny gap in your road, those services aren't providing to your city! Wow, barely noticed it, now I'm getting my people back.
Look at the roads carefully!
That did it for me! Thanks! It was driving me crazy!
I too had that problem and was very frustrating then I discovered that I had destroyed a road to get some simoleons and nor realised that a park had moved stopping the road from connecting. Took me a day to realise lol, so make sure you don’t do the same as me.
