Color change effect not working when I export to Mp4

Hi!!! Very new to AE..I created an animation where a circle is following a path and at certain points it changes colors from pink to orange to yellow, etc. (pic attached for reference) 

When I export this file though, the circle stays at pink and never changes. Is this because the color capability doesn't work when you export as a video? Or can someone advise me on how to keep this change in my video? Needs to be mp4 format