Delivered upstream means that the message you have sent has been submitted to a network but no status report has yet been received from the mobile network.
This means that we cannot ascertain why the mobile network has not yet been able to deliver the message to the mobile phone number and it could be any one of the following:
- Status reports can sometimes be delayed
- This particular network does not support status reports
- The mobile phone is switched off
- The recipients SMS message Inbox is full
- Poor network coverage
- Mobile phone is roaming
- Invalid mobile phone number
The status could change at a later stage from ‘Delivered Upstream’ to either ‘Delivered To Mobile’ or ‘Failed’.