Mine don't either
I pay particular attention to having a very smooth, very clean surface. Also, check out the weight limit of each hook -- they vary greatly. Finally -- attach per instructions... and let "cure" for at least 24 hours -- before placing your object on them. = Success!
Surfaces is too shiny, try a little sandpaper or it isn’t clean enough
What surface are you trying to adhere them too? The area needs to be squeaky clean.
If your walls are plastered with textured finish, command hooks won't adhere.