WhatsApp integration works based on a connection to the Web version of the messenger, so the limits and recommendations will be the same as when using an account from a personal device. 

There can be several reasons for blocking:

• Sending a large number of messages in a short period of time to users with whom there has been no dialog before.
  (initiation of dialog).
• User complaints on your messages. 
  (If they mark them as spam).
• Using the same template messages without personalization, or messages containing links to third-party resources.
• Frequent change of devices\ip-addresses, from which authorization to the account takes place. 
  (If possible, you should use your account from a small number of devices without changing them frequently)

Recommendations and limits that will help you avoid account blocking:

1. WhatsApp carefully monitors mass outgoing messages and the initiation of dialogs with new users, therefore we recommend that you adhere to the following limits:
   

   • For old and active accounts, we recommend initiating up to 20-30 new conversations per day.

   • For new accounts up to 5-10 initiations

   • You can communicate in existing dialogs without any restrictions. 

2. It is recommended to evenly distribute sending messages during the day.
3. If you plan to send welcome messages to new users within the recommended limits - try to diversify your messages so that they are not templated.  It is also a good idea to avoid using links in your first messages

You can learn more about the topic of blocking in WhatsApp on the official website, in the support section: “Temporarily banned accounts” 

Whatsapp support request section.