We have confirmed the issue is now resolved.

We have identified the root cause.

Overly aggressive Cloudflare security policy has been deployed in response of an attack, that also caused some API requests to be challenged by Cloudflare Bot Protection.

We have reverted the change and expecting recovery in minutes.

Send notifications API is partially unavailable for some users. We’re working to fix the problem as quickly as we can. We’ll share another update shortly.