Shopify / Klaviyo SMS not sending — flows, campaigns, consent, TCPA.

Several products can look like “messaging is broken.” They do not share a settings panel. This page is only when a Klaviyo SMS action in a flow or a Klaviyo SMS campaign should send and does not. Email flow messages that never leave Klaviyo are klaviyo-flow-not-sending. Shopify Email / marketing landing in spam or Promotions is shopify-email-going-to-spam. Native or Klaviyo abandoned checkout email is abandoned-checkout-email-not-sending. Failed payment / dunning email is failed-payment-email-not-sending. Back-in-stock / notify-me email is back-in-stock-email-not-sending. Soft-link klaviyo-shopify-notifications when you are choosing which channel owns which ops mail.

Open the customer in Klaviyo → Profiles. Confirm a phone in E.164 (e.g. +1…) and SMS consent status Subscribed. Never subscribed, Unsubscribed, and Suppressed will skip SMS even when email is fine. On a flow, open the SMS message action → Activity / Analytics and note Skipped, Filtered, quiet hours, or no consent. For a campaign, open SMS → Campaigns → the send and confirm Recipients / Sent / Failed. A healthy email send on the same profile does not prove SMS consent — treat them as separate channels.

US SMS marketing is constrained by TCPA-style consent and carrier quiet hours. In Klaviyo account SMS settings, confirm quiet hours / compliance windows for the profile’s timezone. A flow that “should have sent at 11pm local” may be deferred or skipped without a failed campaign status. Double opt-in / keyword consent forms that never wrote SMS Consent to the profile look identical to a broken flow. Do not turn quiet hours off to “force a send” without reading your counsel’s guidance — this playbook only helps you see why Klaviyo skipped the message.

Klaviyo SMS needs a registered sending number (US 10DLC / A2P brand + campaign, short code, or the equivalent for other markets). In SMS account setup, confirm brand / campaign registration is Approved for the destination country on the profile. Pending or Rejected A2P will fail or queue silently while email still works. International destinations outside your enabled countries are skipped. A Shopify checkout phone without a country code can fail formatting before consent is even checked — fix E.164 first.

Confirm the flow status is Live (not Draft / Manual) and the SMS action is enabled (not skipped or deleted after an email-only edit). Confirm the trigger metric still fires from Shopify (Placed Order, Checkout Started, etc.) via Klaviyo → Integrations → Shopify. For campaigns: Scheduled ≠ Sent; a canceled or audience-empty send is not a consent bug. Re-sync or re-authorize Shopify if phones stop landing on profiles after an app update. Soft-link shopify-forms-not-submitting when the SMS opt-in form on the storefront never creates the profile.

Email flow activity with zero SMS attempts is klaviyo-flow-not-sending. Shopify Email in spam / Promotions is shopify-email-going-to-spam. Abandoned cart email silent is abandoned-checkout-email-not-sending. Failed payment / dunning email silent is failed-payment-email-not-sending. Back-in-stock notify email silent is back-in-stock-email-not-sending. Soft-link shopify-back-in-stock-not-notifying when the storefront notify widget never creates the waitlist event. Do not retune email deliverability until you have proven SMS consent and sender registration.

Stay DIY if you can confirm SMS consent, quiet hours, and Live flow status in under an hour. Pay for the Latch AI Ops install when you want lead capture, ops alerts, and a checkout-ready workflow on the live store — including SMS / Klaviyo / consent exception alerts landing in a channel you already check. Clock starts when collaborator access is in. 72 hours. One live store. Written by Nico. No earnings claims. No recovered-revenue or ticket-cut number.

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