It turns out that, indeed, OpenAds was under attack.
Strange, they pick up $20 million in funding last week, throw a big party, get hacked and then cut off the free service and would like to charge us $3,000/month to do what I've been using for free for the past decade.
MERRIKAH!
So I'm transfering to a new, more stable service. Enjoy a couple "ad free" days until it's migrated to a new service and I'll work on a week of credit for my advertisers. Yay.