I cannot put level 3 granary, both 1 and 2 reached level 10 and unlock level 3?

Check in the Build menu when you try to select and built Granary 3. Buildings often have a build requirement such as an amount of money required. It may be that you don't have enough money at the moment.

Granary III is showing as requiring 4.2M money. Unfortunately the game doesn't make it obvious that you need to top up your money first.

If you are still looking for help with this game we have more questions and answers for you to check.