Cannot replace realm world

Hi, I recently purchased a realm on Nintendo switch and trying to upload an already existing world onto the realm. But every time I try to replace the world, it exports successfully but in the "initializing upload" screen it gets stuck and says "An error occurred". Doesn't say what is causing the error or any other details. Tried restarting the device, archiving the game but can't seem to figure out why it won't work. Can someone please help? Thanks