Undelivered, Failed, or Delayed Messages

If your message report shows delivery issues, it’s important to determine whether the message was Undelivered (Failed), or simply Delayed. Each status has different causes and recommended next steps.

Undelivered (Failed) Messages

Download the Message Report

1. Click the Download Report icon in the top right corner of the Message Report.
2. Open the .csv file.
3. Filter Column M: Status for Undelivered.
4. Review Column N: Status Detail for detailed failure information.

Email Failures

Common reasons include:

• Bounced – The email address previously resulted in a hard bounce.
• Blocked – The receiving mail server rejected the message.
• Invalid Address – The email address is incorrectly formatted or no longer exists.

Email delivery may also be delayed or blocked due to:

• Spam filtering
• Corporate firewall rules
• Domain reputation checks
• Greylisting by recipient mail servers

Even if RedFlag successfully transmits the email, the recipient’s mail server may temporarily hold the message before releasing it to the inbox.

Text Message Failures

Common reasons include:

• Invalid phone number
• Landline not text-enabled
• Recipient out of service
• Carrier unable to deliver at time of send
• Carrier filtering or blocking

Carriers return error codes for undelivered text messages. These appear in the message report under:

• Column N: Status Detail

You can view a full list of carrier error codes and their meanings here https://redflagalerts.com/error-codes/

🛡️ Note: Temporary error codes (carrier congestion, handset unavailable, etc.) often resolve automatically. Permanent error codes (invalid number, blocked messaging, opt-outs, etc.) require corrective action.

Short Code Troubleshooting (444222)

If your location sends messages from short code 444222, some recipients may not be able to receive short code messages.

To test:

1. Have the recipient text HELP to 444222.
2. If they receive no response or a message such as Service Access Denied, their carrier may be blocking short code messaging.
3. The recipient must contact their mobile carrier to enable short code messaging on their device.

Voice Call Failures

Common reasons include:

• Invalid number
• Busy line
• No answer
• No voicemail greeting detected

If a call is unanswered and a voicemail greeting is not detected, the system retries up to 3 times before marking the call as undelivered.

Delayed Messages (Throughput & Queuing)

In some cases, messages are not failed — they are delayed due to throughput limits and carrier processing.

Understanding the delivery flow helps explain why:

Message Delivery Flow

1. RedFlag queues the message internally.
2. The message is transmitted to our carrier aggregator.
3. The aggregator routes the message to downstream carriers.
4. The carrier delivers the message to the end recipient.

Each step includes processing limits that can impact delivery timing.

Text Message Throughput (10DLC)

For 10DLC messaging, throughput is determined by your brand registration and Trust Score with The Campaign Registry (TCR).

• Higher Trust Score → Higher throughput → Faster delivery
• Lower Trust Score → Lower throughput → Messages delivered more gradually

When sending high-volume text messages:

• Messages are delivered in batches.
• Delivery may take several minutes depending on your approved throughput rate.
• Carrier congestion can further impact timing.

Throughput is regulated by carriers and cannot be manually increased outside of approved limits.

Email Throughput

Email throughput is generally comparable to text messaging but depends heavily on:

• Recipient mail server throttling
• Spam filtering
• Domain authentication (SPF, DKIM, DMARC)
• Corporate firewall scanning

Even after successful transmission, receiving servers may temporarily hold or scan messages before final delivery.

Voice Call Throughput

Voice calls have the lowest throughput compared to SMS and email.

RedFlag supports up to 2,000 concurrent calls at one time.

For high-volume voice broadcasts:

• Calls are placed in batches.
• If the recipient count exceeds 2,000, additional calls are queued.
• Longer voice messages increase total broadcast duration.
• Retry attempts also extend completion time.

Total delivery time depends on:

• Number of recipients
• Call length
• Retry attempts
• Carrier routing performance

Summary

If you experience widespread failures or unexpected delays, contact Support and provide:

• Message name and date sent
• Channel used (Text, Email, Voice)
• Approximate send time
• Sample affected recipients

This allows our team to review carrier logs and routing diagnostics to assist further.