SMS deliveries with 'Refused' status
Hi,
I'm trying to understand what is the cause of failing SMS deliveries with status 'Refused'. In the Delivery Log Qualification I see many of them with the similar message:
SR Generic UNDELIV {number}|#MESSAGE#,
where {number} may be different.
All the entries, which I checked have also Qualification status 'To qualify', which in my understanding means that nothing will be done with them.
My question is, what to do is such case? Does the change of Qualification status manually to 'Keep' makes any sense? I want to learn why they are refused and, if possible, to prevent being refused in the future.
Thanks for any cues.
Best,
Dominik