This page lists the limits your integration should handle cleanly.
429)If you send requests too fast, you may get 429 Too Many Requests.
Client behavior:
429)If you configured a PAYG message cap for a token in a specific date window, sendMessage can return 429 when the window is active and the limit is reached.
403)If you enabled IP allowlist for a token, requests from other IPs return 403 Forbidden.
401)If a token is disabled/inactive, requests return 401.