403 errors for me… Removed my account from Sync, tried to sign back in but get 'Invalid login' messages, even with the same credentials I'm using to login via the browser and post this comment.
Edit: Sync returned the 'invalid login' error continually until I disconnected my VPN, then I could add the account again… Seems Lemmy.world is blocking at least some ProtonVPN servers right now, as switching the VPN back on post-login generates the 403s again. Nasty.
When connected to my VPN, which I am as much as possible, I can not vote, save posts or comment (presumably I can't post either) on lemmy.world. I can understand the admins' motivations given recent troubles, but it isn't a reasonable, privacy-considerate solution.