If you received the file from someone else, ask them to save it as a "Compatibility" project. Go to File > Save As > Save a Copy as [Previous Version]. Step 2: Identify Missing Plugins
How to Fix the After Effects Error: "Asked to Create Unknown Property of Type" If you received the file from someone else,
If the project file itself is slightly corrupted, you can often bypass the error by importing it into a fresh workspace rather than opening it directly. Open After Effects and create a brand new project. Go to File > Import > File. Select the problematic .aep file. If you received the file from someone else,
Hold down Ctrl+Alt+Shift (Windows) or Command+Option+Shift (Mac) while launching the program. If you received the file from someone else,
Check the "Effects" panel for any entries labeled "Missing."