Your disk cache folder is on a drive that does not have enough available space to safely store the full amount specified in your preferences. I can't click on anything not even the preferences. Please
make more space available or go to Media & disk cache preferences to change the folder or maximum disk cache size
Close the dialog box. Are you then able to interact with After Effects normally? You should be able to. If so, make the recommended modification---i.e., decrease the size of the allocation for the disk cache or move the disk cache to a drive that has more free space.
You have not provided any proper system information or other technical details, so pardon me, but your post is useless. Nobody can help you without the relevant information.