Issue has cleared from Meta's side, Meta's WhatsApp API service is back working

Services are slowly restoring back to WhatsApp

The issue has been reported on YC's hacker's news, still not acknowledged by Meta yet.
https://news.ycombinator.com/item?id=48504034

We've confirmed it's a Meta-scale global issue, not related to our own implementation or usage.
Meta has not confirmed yet officially, but we've found the same issue on their official reddit.

https://www.reddit.com/r/WhatsappBusinessAPI/comments/1u3vva2/is_the_whatsapp_cloud_api_down_or_just_me/

We're investigating an issue from Meta's own Auth layer causing WhatsApp API responses to error or timeout.
OTPs are falling back through Telegram & SMS