Deliverability
SMS delivery reports (DLR): what each status really means
What an SMS delivery report is, what DELIVRD, UNDELIV, EXPIRED and REJECTD mean, why 'delivered' isn't proof of reading, and why DLRs go missing or wrong.
7 min read
Articles tagged “Delivery receipts”
3 articles.
Deliverability
SMS delivery receipts vs HLR lookup: before or after you send
A delivery receipt reports what happened after you sent an SMS. An HLR lookup asks the network before you send. What each can see, miss and cost.
7 min read
Deliverability
Why SMS messages aren't delivered: a cause tree with fixes
A cause tree for undelivered SMS: invalid numbers, unreachable phones, wrong line types, carrier filtering and handsets, with a fix for each.
7 min read
