Can't upload using android target, keep getting prefab missing

So, whenever I click the “Build & Publish” button it gives me the “prefab.unity3d” does not exist or is missing. I need help for that. I don’t understand why it happens and I already checked a lot of reddits but nothing works. Note: I have the recommended version of unity, the VRCSDK3 and the unitypackage that contains the avatar. If someone could help me I would be really happy about it.

You have compiler error(s), the filenotfound / prefab.unity3d error is irrelevant to solving it.
The reason is because that filenotfound / prefab.unity3d error is a symptom, and not the cause of it.

I would have to see a picture of your console showing with errors showing (they are red) to help you solve this.