Same problem, parts of animation disappears

I've posted about this problem before and got the answer "your computer can't handle the program". Well now I've tried to animate at my university and these computers are made for graphics design and animation... and the animation is still lagging.

Layers from my animated gif disappears one by one once exported. In Adobe Animation it doesn't disappear but the playback is very slow. Don't know how to fix this..

I attached the exported gif below.