Short answer is try and clear your browser cache, close and reopen your browser, and see if that helps. If it does not send in a bug report from within that game and the server state can be refreshed from our end.
General information:
When you see orders not being carried out you should check your server state connection. This is an icon in the lower right corner with two half circle arrows. If you hover your mouse over it the state will pop up:
Server State Connected: This is the proper connection when the arrows are stationary and means there is no communication difficulty with the server
Server State Connecting or Waiting for Response: Will show the arrows in motion, and indicates that there may be an issue with server communication. Orders may not be transmitted to the server, so that commands to move or attack may not be carried out.
Server State Disconnected: Indicates that your orders definitely are not reaching the server and you have an internet connection problem.
One sign of these is when your units do not show an arrival time or travel time when you give orders. The arrival time and travel time come from the server, so when those are visible you can be sure your orders are carried out. Otherwise units may move within your browser, but will be back where they started when you load the game again.
Typically these issues can be corrected by reloading the browser tab. Occasionally you will have to take the step of clearing your browser cache, closing and reopening the browser.
If you try to attack/move something that doesn't exist, it will go "Server state differs from client". This is because the server state differed from the client (aka the map is different to what actually is there).
Zooming out, a partial refresh, or a full reload should all fix this issue. Some of the time you will need to do the following: Clear the browser cache, close the browser, reopen the browser, Clear browser cache AGAIN, then try to reload the game.
