Hmm, I would have expected it to start working again. Something is not right…
Sidekiq should be working in the background even though the server returns errors. An increasing number of enqueued jobs could be normal, as long the the count of processed jobs increased over night as well. Did it?
You could try taking a look at Sidekiq in the rails console:
./launcher enter app rails c Sidekiq::Stats.new
You can take a look at API · mperham/sidekiq Wiki · GitHub if you want to know what else you can do with the Sidekiq API.