Losing frames when importing animation from c4d to unity

Hi! I 'm in a big trouble! When i import an animation which has 90 frames in C4D to unity it seems that half of the frames disappear! Only the first half can be played. I've already selected the start and end frame in Unity's inspector, but it doesn't work. Is there anyone can help? THX!

I heard that there is some bug like that in Cinema4D exporter. Could you try exporting from Cinema4D to fbx manually and then import back to Cinema4D and see if all keyframes are still there.