Meta can't take payment for this WhatsApp Business Account, so messages may not send.
Meta bills WhatsApp message charges to your own WhatsApp Business Account, not through Avox. Meta tried to charge the payment method on that account and couldn't, so WhatsApp may refuse to send your messages (Meta's error 131042). Avox shows this on Billing, in the alert bar and by email to every Admin, once per problem.
On Billing in Avox, click Fix in Meta to open Billing & payments in Meta Business Suite, and pick this WhatsApp Business Account.
Add a payment method, or update the card that expired or was declined.
Pay any amount Meta shows as due, or ask Meta to raise a credit line that's over its limit.
Back on Billing in Avox, click Check again. It can take a few minutes for Meta to show the change.
Still stuck? Send AVX-3440 to hello@theavoxai.com along with what you were doing when it happened.