Please make sure that you have set a username on the vanilla mojang launcher (Account button at the top -> Manage Minecraft: Java Edition Profile -> In opened window, choose Profile Name and set a name if you didn't already).
If you have that, make 300% or 400% sure you are ACTUALLY using the right email. We've already had people swear up and down they were using the right email, only to find out they were, in fact, not using the right email.