What does “delivered upstream” mean?
This means that the SMS has been submitted to a network but no status report has been received from the mobile network. There are several factors that can contribute to the message delivering swiftly by the carrier:
- Recipient signal strength and connection to the network
- Problems with the network
- Carrier issues
To track down the delay, please check your delivery reports and error codes. For more information, please contact your account manager for more details or get in touch with email@example.com.