EDIT: THE ISSUE HAS BEEN RESOLVED. APPARENTLY, ALL IT TOOK WAS FOR ME TO RELOGIN TO THE INSTANCES. SED LYF INDEED.
I'm logged into 3 instances, the fossware instance, the lemdroid instance and lemmy.world. But anytime I try to vote or comment on a lemmy.world post, it shows me the "Not Logged In" toast notification.
So to be clear, what you're saying is when you are viewing a lemmy.world post on lemdro.id, the upvote button isn't working? Strange, I cannot reproduce that behavior. I did do some rather major infrastructure updates in the last few hours so maybe try again?