I got this answer when sending 500 messages in batches by 300 (chatapi.viber.com/pa/broadcast_message - sending REST URL). It was working until last week i start getting this as response:
(
[status] => 23
[status_message] => maximum free messages from Bot exceeded.
[message_token] => 5748679331176400537
[chat_hostname] => SN-CHAT-02_
)
Doea anybody know What is this maximum? Was unable find it in Viber doc!
Nothing is write about this in Viber API documentation for broadcast_message (https://developers.viber.com/docs/api/rest-bot-api/#broadcast-message)!