for those of you who cant get the hotkeys to be saved , try this :
1 - open a game room
2 - in the menu click on "Game"
3 - check "[You must login to view link]"
4 - launch the game ( the game will start like in offline mode )
5 - go to options :
* now either you will find that you dont have have a profil and you will be asked to
choose a name .
* or u will delete your current name and create a new one .
6 - close the game and uncheck "start at single player menu " and launch the game and set
your hotckeys

PS : if you follow all steps and the problems is still not fixed , then :
- go to C:\Program Files (x86)\Voobly\gamedata
- delete "aoc" folder
- restart voobly
- open a game room and uncheck the "HD Hotkeys" mod (if you have that mod installed )
- repeat the steps from step 3 to step 6

warning
setting hotkeys on voobly works like if you were setting hotkeys on normal aoc .
you can't give buildings same hotkeys (not like aoc hd on steam)