SMS Issues

This guide covers the most common problems with outbound SMS on Volume Reach and how to resolve them. Find the issue that matches your situation.

SMS Messages Are Not Delivering

Problem: You sent an SMS broadcast or individual message but recipients are not receiving it.

Solution: The two most common causes are registration status and configuration. Check each of the following:

A2P 10DLC registration must be Approved. In the United States, all business SMS traffic must be registered with carriers through the A2P 10DLC program. If your registration is Pending, In Review, or shows any error, messages may be blocked. Go to Settings > Compliance > A2P Registration to check your status. If registration is still in progress, you will need to wait for carrier approval before messages will reliably deliver.
Phone number is attached to a messaging service. Your outbound number must be linked to an active messaging service in your account. Go to Settings > Phone Numbers and confirm the number is connected.
Wallet balance is sufficient. SMS credits are consumed with each message sent. If your balance is at zero, messages will not go out. Go to Billing > Wallet to check and add funds.

For help completing registration, see A2P 10DLC Registration.

High SMS Failure Rate

Problem: A large portion of your messages are failing or being reported as undelivered.

Solution:

Your list may contain landline numbers. SMS only works for mobile phones. Landline numbers will always fail. Review your contact list and filter out any non-mobile numbers before sending.
Contacts may have previously opted out. Volume Reach automatically suppresses messages to contacts who have replied STOP. If your list includes previously opted-out contacts, those will show as failed or suppressed. This is expected behavior and required by law — you cannot send SMS to contacts who have opted out.

AI SMS Agent Is Not Replying

Problem: Contacts are responding to your messages but the AI agent is not sending replies.

Solution: Check each of the following:

An SMS agent is assigned to the campaign. The campaign channel must have an AI SMS agent selected. Open the campaign, go to the channel settings, and confirm an agent is assigned and set to Active.
The contact has not opted out. If a contact previously replied STOP, the system will suppress all outbound messages to them, including AI replies. This cannot be overridden — it is a legal requirement.
Your plan includes AI SMS. Automated AI SMS replies are available on the Growth plan and above. If you are on the Launch plan, upgrade to enable this feature.

See AI Auto-Reply for setup instructions.

Messages Are Being Filtered by Carriers

Problem: Messages are sending from your account but recipients are not receiving them — or they are being blocked without a clear delivery failure.

Solution: Carrier filtering is applied when messages resemble spam or violate messaging guidelines. Common causes and fixes:

Message content contains flagged language. Phrases like FREE, URGENT, ACT NOW, LIMITED TIME, or all-caps promotional language trigger carrier filters. Review your message templates and remove or soften this type of language.
Messages are too long or formatted oddly. Keep messages concise and conversational. Avoid excessive punctuation, symbols, or emoji-heavy content.
A2P registration language must match. Your campaign registration with carriers must include "Message frequency varies" in the opt-in disclosure. Volume-based language like "You will receive X messages per week" is rejected by carriers and can result in filtering across all your messages. Check your registration details under Settings > Compliance > A2P Registration.
Ensure full A2P compliance. Carriers filter messages from businesses that have incomplete or inaccurate A2P registrations. Make sure your brand profile and campaign use case are accurate and fully approved.

Opt-Out Is Not Working

Problem: A contact replied STOP but is still receiving messages.

Solution: The opt-out system is automatic. When a contact texts STOP to your number, Volume Reach processes the opt-out and suppresses that contact from future outbound messages.

If a contact reports they are still receiving messages after opting out:

Confirm the contact texted STOP to the correct number — the same number your messages are being sent from.
Check if messages are coming from a different number in your account. Opt-outs are tied to a specific number, not your entire account.
If the issue persists and you believe there is a system problem, contact support immediately. Sending messages to opted-out contacts violates carrier rules and federal law (TCPA).

Broadcast Is Stuck in "Sending"

Problem: You launched a broadcast and it has been stuck in "Sending" for a long time without completing.

Solution: This is expected behavior for large broadcasts. Volume Reach sends messages in batches to stay within carrier throughput limits and avoid triggering spam filters. A large broadcast to thousands of contacts can take minutes to hours to complete, depending on its size.

Go to SMS Broadcasts and open the broadcast to view its progress and current status.
Do not cancel and relaunch the broadcast — this will send duplicate messages to contacts who have already received it.
If the broadcast shows no progress after several hours or displays an error, contact support with the broadcast name and send date.

For information on send limits and estimated delivery times, see Broadcast Limits.