Multidrop - SMS Not Delivering/Reply Failures

📱 Help: SMS Delivery, Charges, and Confirmation Rules

This guide explains when SMS messages are charged, why some may not be delivered, and what rules apply to SMS confirmations for deliveries.

đź’· When Am I Charged for an SMS?

SMS credits are charged as soon as the message is submitted to our SMS supplier, even if the message ends up being rejected by the recipient’s phone or network.

Why?
Triggering the send still incurs a cost, even if the message doesn't reach the phone.

You will not be charged in these cases:

  • The number is missing or clearly invalid
  • The SMS is blocked before it’s submitted to the supplier

đźšš What Happens After the SMS Is Sent?

Once your message is submitted to the supplier, the process is out of our hands unless:

  • The supplier blocks the SMS (we can request they review or unblock it)

If the supplier accepts the SMS:

  • It is passed on to the recipient’s phone network
  • Delivery problems from this point are usually caused by the recipient’s carrier or device

⚠️ Common SMS Delivery Issues

These are the most common reasons an SMS might not be delivered:

1. Invalid or Inactive Number

  • The phone number can't accept SMS
  • It might not support SMS or is deactivated

2. Phone Switched Off

  • The message can’t be delivered if the phone is off
  • SMS has a time limit (validity period); if the phone stays off too long, the message fails

3. Network Restrictions

  • The number is on a Do-Not-Disturb list
  • There are unpaid bills or account issues
  • The user must contact their mobile provider to resolve this

4. No Signal / Out of Network

  • The phone is on, but has no network connection
  • Sometimes, issues with the SMS delivery system (A2P network) can also cause failure
  • Restarting the phone often helps

5. Roaming Numbers

  • SMS to roaming numbers may not deliver depending on agreements between networks
  • We can’t guarantee delivery to users abroad

6. Local Restrictions

  • Some countries block SMS with certain content or from certain senders
  • If you're sending internationally, check local SMS regulations

đź“„ More details: Country Restrictions and Regulations

📵 iPhone & Android Message Filtering

📆 SMS Confirmation Settings – Delivery Deadlines

By default, our system requires delivery confirmations to be submitted before Friday at 6:00 PM for any deliveries taking place over the weekend or on a Monday.

This is to prevent last-minute changes that can cause delays, routing issues, or failed deliveries.

Why it matters:
If a customer confirms a Monday delivery on Saturday, and then cancels it, there’s no one available to action the changes before Monday. This often leads to complaints.

đź’¬ Changing the Cut-Off Time

If you have your own internal process or staffing setup and want to extend the confirmation window, just let us know.

Here are some examples of cut-off changes you can request:

  • “Monday deliveries can be confirmed until Saturday at 5:00 PM”
  • “Recipients can confirm their delivery until 11:59 PM the night before delivery, regardless of the day”

Once agreed, we can update your system rules accordingly.

❌ My SMS Wasn’t Delivered – What Should I Do?

  1. Check that the number is correct and SMS-capable
  2. Ensure the phone is on and has signal
  3. Ask the user to check their SMS inbox, including any filtered sections
  4. If the issue continues, ask the recipient to contact their mobile provider

If you’ve confirmed that the number is correct and there are no known restrictions, but messages are still not being delivered, please contact us so we can look into it with our SMS supplier.