SMS failures can happen for several reasons, including compliance issues, permission or configuration errors, recipient opt-out status, timing restrictions, or international account setup requirements.

This guide outlines the most common causes of SMS failures on the platform and provides troubleshooting steps to help identify and resolve them.

SMS sending requires Twilio compliance for each studio location. If Twilio compliance has not been completed or is still pending approval, SMS messages will fail to send. This applies to both marketing and transactional SMS.

Users must have the appropriate SMS permissions assigned in order to send messages or access SMS functionality. Without the correct permissions, SMS icons, inboxes, or sending options may not appear. The following permission is typically required: can_manage_sms.

For SMS conversations to appear in the SMS inbox, two-way communication must be properly configured. If two-way communication is not enabled, outbound messages may be sent successfully, but replies and conversations will not appear in the inbox.

Contact support to confirm two-way communication is configured.

Transactional SMS must be enabled at both the system level and in specific features that rely on SMS notifications.

For example, features such as Waitlist Quick Fill require that transactional SMS be enabled to send notifications.

Customers must opt in to receive SMS communications. If a customer has previously replied with keywords such as STOP, they are automatically opted out and will no longer receive SMS messages.

Some carriers only recognize specific opt-out keywords. For example, replying with unsubscribe may not always process correctly, while STOP is universally recognized and enforced by carriers.

Certain SMS notifications rely on reservation timing windows and automation rules.

If a cancellation occurs outside the configured auto-fill window or too close to the reservation cutoff window, SMS notifications may not send.

Example: If a customer cancels a reservation shortly before class starts and the reservation cutoff window has already passed, waitlisted customers may not receive SMS notifications for the open spot.

International accounts may require additional setup steps before SMS can be activated. Unlike North American accounts, international SMS activation often requires manual carrier approvals, regulatory documentation, and custom messaging service configuration. Standard activation workflows may fail due to:

Certain message content may be blocked by carriers or messaging providers.

Public URL shorteners such as bit.ly are commonly blocked because carriers require branded or recognizable domains to reduce spam and phishing attempts.