Ecobee went "unavailable," can't re-add integration

A week or so ago, all of my ecobee sensors went “unavaillable” and I couldn’t get them back. So I removed the integration, but I can’t add it again. When entering the API key, I get “error requesting PIN from ecobee.” I’ve verified that the API key is correct, and have even deleted/recreated all apps in the ecobee developer portal. No luck.