Receiving SMS and routing to an email
There are two ways to receive SMS. You can receive them as SIP MESSAGE, or you can have them delivered from your provider using an API.
SIP MESSAGE
As first step, please check if your system can receive messages using SIP protocol. In sip.conf check if you have the following rows:
accept_outofcall_message=yes outofcall_message_context=astsms auth_message_requests = yes
Add if not, then reload the sip module
API
In your Provider, configure the URL https://.../pbx/receivesms.php