mastodon.online is currently experiencing delays in the processing queue and general slowness due to much increased demand. I am working on increasing capacity. Sorry for the inconvenience!
Upgraded capacity, it's chewing through the processing queue now, should catch up soon. Slowness seems to have subsided too. That's another 12-hour workday done. 
@Gargron Thank you! I hope you'll have a good rest now :)