# Klaviyo: Yahoo PH01 Block — Email Bounces to Yahoo/AOL Recipients

> Klaviyo status incident “Yahoo PH01 Block — Email Bounces to Yahoo/AOL Recipients” on 2026-07-02: impact minor (vendor’s label), 2.0 h, 2 update(s). Archived by Rewindex.

Canonical: https://rewindex.com/company/klaviyo/incidents/0s66874fm4zc
Last updated: 2026-07-02T14:17:54Z

- Impact (vendor’s label): minor
- Status: resolved
- Started: 2026-07-02 12:17 UTC · Resolved: 2026-07-02 14:17 UTC · Duration: 2.0 h
- Updates: 2 · Affected components: Email Deliverability, Email Sending - Email Deliverability
- [Vendor status page: https://stspg.io/6j2x00l2v83f](https://stspg.io/6j2x00l2v83f)
- [Company: Klaviyo](https://rewindex.com/company/klaviyo.md)

## Timeline of updates

- **investigating** 2026-07-02 12:17 UTC: Starting at 02:30AM US/Eastern on 07/02/2026, a subset of customers are currently experiencing an increase in bounced emails to Yahoo and AOL recipients with the reason of "554 Message not allowed - \[PH01\] Email not accepted for policy reasons.". Our Engineering and Deliverability teams are actively investigating and working with Yahoo to resolve the issue. We do not recommend resending to those bounced recipients at this moment in time.
- **resolved** 2026-07-02 14:17 UTC: The block within the Yahoo infrastructure that resulted in these elevated bounces has been resolved. Customers can safely resend to bounced recipients from this time period. This incident has been resolved.

## Cite this

Status incident (vendor impact label: minor) posted by Klaviyo, started 2026-07-02 12:17 UTC, resolved after 2.0 h, 2 update(s).

- Canonical URL: https://rewindex.com/company/klaviyo/incidents/0s66874fm4zc
- Citation: Klaviyo, “Yahoo PH01 Block — Email Bounces to Yahoo/AOL Recipients” (2026-07-02 12:17 UTC). Archived by Rewindex: https://rewindex.com/company/klaviyo/incidents/0s66874fm4zc (CC BY 4.0).
- Markdown link: `[Klaviyo: Yahoo PH01 Block — Email Bounces to Yahoo/AOL Recipients (2026-07-02)](https://rewindex.com/company/klaviyo/incidents/0s66874fm4zc)`


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Canonical: https://rewindex.com/company/klaviyo/incidents/0s66874fm4zc · Markdown: https://rewindex.com/company/klaviyo/incidents/0s66874fm4zc.md · JSON: https://rewindex.com/api/v1/companies/klaviyo/incidents/0s66874fm4zc · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-11-04T21:54:58.653Z