WhatsApp in Zoho CRM Plus: inbound works, every outbound message fails with crm.bm.msg.failed.undefined since Oct 14 (business stopped)

WhatsApp in Zoho CRM Plus: inbound works, every outbound message fails with crm.bm.msg.failed.undefined since Oct 14 (business stopped)

Hello Zoho team and community,

We are Roxo Inc, a Zoho CRM Plus customer in Florida. WhatsApp is our main sales and support channel, and since October 14, 11:11 AM EDT we cannot send any WhatsApp message from Zoho CRM. We are facing a large drop in sales because we cannot reply to customers.

What works:
1. Our US number is connected in CRM Business Messaging, on our existing WhatsApp Business Account.
2. Inbound messages arrive in the CRM Messages module normally.
3. On Meta's side the number is CONNECTED on the Cloud API, and the account health shows can_send_message AVAILABLE.

What fails:
1. Every reply sent from CRM fails with crm.bm.msg.failed.undefined, for every user. The real Meta error is not shown.
2. A new WhatsApp template created in CRM shows "Failed" and never reaches Meta.
3. Our Brazil number, also CONNECTED on Meta, is greyed out in "Add New Number" and cannot be selected, although it is not used in any other app or Zoho service.

In short, everything outbound from Zoho to Meta fails, while inbound from Meta to Zoho works.

How the support process went: since October 14 the case has gone through 5 tickets (169227250, 169246718, 169314751 and others opened from replies), 5 different support agents and one meeting with support and the account manager. Every answer has been "escalated to developers, no ETA". After more than a day, we still have no Meta error code, no root cause and no time for a fix.

Questions to the community and the Zoho team:
1. Has anyone seen crm.bm.msg.failed.undefined after reconnecting WhatsApp in CRM Plus, and how was it fixed?
2. Can someone from the Zoho CRM product or engineering team look at ticket 169246718 today?

Thank you.
Philippe, Roxo Inc