Queue automatic messages so normal WHMCS cron runs send them in batches. Quiet hours let queued work wait during a daily window; they are not a blanket pause for every message the module can send.

Set the queue behaviour

1. Open PD Modules → SMS Manager → Settings.
2. Enable Queue SMS and send on cron.
3. Review Messages per cron run for your intended volume and provider limits.
4. Review Try a failed message up to. This is the total number of attempts, including the first attempt.
5. Set Quiet hours, save, and check Health for any invalid setting.

With queueing disabled, automatic messages can be sent inline instead. Quiet hours and queue retry handling apply to queued work. Changing this setting is not a substitute for reviewing existing pending messages or individual trigger routing.

Name the timezone explicitly

Use a window such as `21:00-08:00 Europe/London` if those are the hours you intend. A named timezone avoids relying on a different clock used by a web request or cron process. Blank means no quiet-hours window; an invalid window is not a reliable sending pause.

Without a named timezone, the server clock is used. Check the effective configuration rather than assuming a campaign’s browser time controls this window.

Understand the exceptions and retries

Manual messages, staff alerts and sign-in codes are not held by quiet hours. A scheduled campaign is also dependent on the queue, due time, quiet hours and cron; its selected time is not a guarantee of immediate delivery.

Definite queued failures can be retried within the configured attempt limit. A timed-out, indeterminate send is marked Unknown and is not automatically retried because it may already have arrived.

If the queue does not progress, your hosting team should compare the original pending work with the window, scheduled time, effective timezone, normal cron operation, gateway and recorded error. Preserve the original request; do not clear queue records or repeatedly resend to diagnose it.

See the PD SMS Manager WHMCS guide for related tasks, or explore PD SMS Manager.