What version of AE? 12.2.0? 11.0.4? 9.5.0?
Have you tried turning your computer off and on again? I've seen that fix similar issues.
Yes, I had tried that earlier. Restarting did not work, however, I did find another solution:
I removed java and now all works well.
I also had this rendering to large Quicktime files. Clearing the cache helped (I think!) as mine was maxed out at 64GB at the time