You are logging into lemmy ml instance which is at capacity so it's struggling. I created another account on another instance and now all is fine while previously I couldn't login either.
edit: as @[email protected] correctly mentioned, OP asked about the lemmy.click
instance which is a mistake on my part. That still doesn't completely solve the issue as the Reddit exodus is putting a massive strain on all instances as more and more are getting removed from the suggestion list due to being at capacity. This along with the platform being not mature enough is going to cause issues. Best way to resolve these, is to place them in the github issues with descriptions.