Down for 5 days now. I just started using this last week on my first game and it worked perfectly for 3 days. You say it's common for the servers to go down?
Yeah, at least once a week, usually it's during the weekends (in my timezone) so I assume it was just weekly maintenance, but in this case I assume the servers crashed and the developer didn't know. I should probably send them an email about it or talk to them on discord.
edit: just now sent him an email, so fingers crossed!