# Configure SMS Delivery Windows

An SMS delivery window controls when Engage Studio may send messages for a campaign. Use a delivery window to align a campaign with the audience's jurisdiction and applicable quiet-hours requirements before you launch it.

## How Delivery Windows Work

The delivery window applies uniformly to every recipient in the campaign audience. Engage Studio does not resolve a different window for each recipient. If an audience spans time zones or jurisdictions with different restrictions, split the audience in the CDP and create campaigns with appropriate windows.

Messages outside the configured window are blocked before delivery and recorded as `quiet_hours_blocked`. Engage Studio does not retry these messages automatically.

## Configure a Delivery Window

1. Open the SMS campaign's delivery-time settings.
2. Select the IANA **Timezone** for the campaign window, such as `America/New_York`.
3. Set **Allowed Start** to the earliest time Engage Studio may send, such as `08:00`.
4. Set **Allowed End** to the latest time Engage Studio may send, such as `20:00`.
5. For an Always-on Campaign, configure any available weekday overrides.
6. Save the campaign settings.


Engage Studio SMS Allowed Delivery Time settings with timezone, start, and end fields
## Choose the Window for Your Audience

US federal TCPA rules generally restrict promotional messages outside 8:00 AM–9:00 PM in the recipient's local time. Some states and jurisdictions use stricter limits. Choose a window that meets the requirements for the audience you selected; Treasure AI does not determine each recipient's legal jurisdiction for you.

Important
The sending organization is responsible for consent, audience segmentation, and compliance with applicable regulations. Configure a window that is appropriate for the audience rather than assuming that one national default applies to every recipient.

## Handle Blocked Messages

Use the delivery events table to find messages recorded as `quiet_hours_blocked`. To send those recipients another message, create a new campaign after correcting the audience or delivery window. A blocked message is not automatically retried.

See [View SMS Delivery Events](/ja/products/marketing-cloud/engage-studio/channels/sms/view-sms-delivery-events) for event locations and [SMS Message Requirements and Limits](/ja/products/marketing-cloud/engage-studio/channels/sms/sms-message-requirements) for related send constraints.

## Related Pages

- [Create an SMS Campaign](/ja/products/marketing-cloud/engage-studio/channels/sms/create-sms-campaign)
- [Manage SMS Consent and Opt-Outs](/ja/products/marketing-cloud/engage-studio/channels/sms/manage-sms-consent-and-opt-outs)
- [Troubleshoot SMS Delivery](/ja/products/marketing-cloud/engage-studio/channels/sms/troubleshoot-sms-delivery)