Problems Uploading World to Server

Hi! I've been trying to upload one of my personal worlds to aternos, but every time I do it, the world gets corrupted! I've uploaded it with the file both zipped and unzipped but it appears that new chunks/biomes spawn where they're not supposed to be. i.e. a snowy hills biome spawning directly in the middle of what was a plains village. I do have builds and plan on turning this server into an SMP so I don't really want to have to start from scratch/play on a corrupted world! I've attached an example of the world being corrupted. I'm not sure how to fix this please help!

Quote from Roman

Please try to upload the world, then disable optimize on the worlds page

It worked! Thank you so much