SMS received from whatsapp but cannot reply to those SMS

[3CTEL]

Hey,

I have followed the 3CX-Whatsapp integration guide and I am receiving SMS from Whatsapp numbers but when I am unable to reply back. Red cross appeasers on the SMS when I reply. On event logs it shows this error:
Failed to send message(s) to the provider 'whatsapp' from 'xxx-xxx-xxxx' to "xxx-xxx-xxxx''. Exception: {"error":{"message":"(#131030) Recipient phone number not in allowed list","type":"OAuthException","code":131030,"error_data":{"messaging_product":"whatsapp","details":"Recipient phone number not in allowed list: Add recipient phone number to recipient list and try again."},"fbtrace_id":"ALpFIwJ8RkARkKGp0q0VDkT"}}

Can anyone advice what am I missing in configuration? I have tried with multiple numbers and error is same. Thanks!

 

[TheodorosG_3CX]

Is the number in E164 format?

 

[3CTEL]

yes

 

[TheodorosG_3CX]

This error though comes from whatsapp, is there any restriction on the allowed numbers?