# SparkPost: Elevated API and UI Errors: 503 authentication errors - May 11th through May 14th

> SparkPost status incident “Elevated API and UI Errors: 503 authentication errors - May 11th through May 14th” on 2016-05-20: impact none (vendor’s label), 0 min, 1 update(s). Archived by Rewindex.

Canonical: https://rewindex.com/company/sparkpost/incidents/1cflhb2190ks
Last updated: 2016-05-20T21:28:00Z

- Impact (vendor’s label): none
- Status: resolved
- Started: 2016-05-20 21:28 UTC · Resolved: 2016-05-20 21:28 UTC · Duration: 0 min
- Updates: 1
- [Vendor status page: https://status.sparkpost.com/incidents/1cflhb2190ks](https://status.sparkpost.com/incidents/1cflhb2190ks)
- [Company: SparkPost](https://rewindex.com/company/sparkpost.md)

## Timeline of updates

- **resolved** 2016-05-20 21:28 UTC: SparkPost APIs and the UI had high error rates during several periods of time starting on Wednesday May 11th 2016 through Saturday May May 14th. During these periods customers received the following error intermittently, and at times very frequently, HTTP code 503 "Unable to contact authorization service.” A similar authentication error was returned if using SMTP. During the following times we had elevated error rates on all APIs and the UI. May 11th 13:28 UTC - May 11th 14:15 UTC May 11th 14:59 UTC - May 11th 15:15 UTC May 11th 17:19 UTC - May 11th 17:42 UTC May 11th 20:17 UTC - May 11th 20:38 UTC May 12th 00:42 UTC - May 11th 00:49 UTC May 12th 05:17 UTC - May 12th 05:23 UTC May 12th 07:16 UTC - May 12th 07:22 UTC May 12th 09:03 UTC - May 12th 09:08 UTC May 12th 10:59 UTC - May 12th 11:16 UTC May 12th 18:29 UTC - May 12th 18:31 UTC May 13th 04:10 UTC - May 13th 04:25 UTC May 13th 08:17 UTC - May 13th 08:35 UTC May 14th 19:53 UTC - May 14th 20:16 UTC This severely impacted the ability to submit new transmissions via REST and SMTP API. However, any transmission that was accepted with a 200 or a 250ok was queued for delivery and processed. Impact ends after a reliable mitigation strategy is implemented and all alerts clear May 14th 20:16 UTC Root cause fixed in production May 16th 21:30 UTC

_From the vendor’s published history: only the final update text is available for incidents before Rewindex began polling this page._

## Cite this

Status incident (vendor impact label: none) posted by SparkPost, started 2016-05-20 21:28 UTC, resolved after 0 min, 1 update(s).

- Canonical URL: https://rewindex.com/company/sparkpost/incidents/1cflhb2190ks
- Citation: SparkPost, “Elevated API and UI Errors: 503 authentication errors - May 11th through May 14th” (2016-05-20 21:28 UTC). Archived by Rewindex: https://rewindex.com/company/sparkpost/incidents/1cflhb2190ks (CC BY 4.0).
- Markdown link: `[SparkPost: Elevated API and UI Errors: 503 authentication errors - May 11th through May 14th (2016-05-20)](https://rewindex.com/company/sparkpost/incidents/1cflhb2190ks)`


---
Canonical: https://rewindex.com/company/sparkpost/incidents/1cflhb2190ks · Markdown: https://rewindex.com/company/sparkpost/incidents/1cflhb2190ks.md · JSON: https://rewindex.com/api/v1/companies/sparkpost/incidents/1cflhb2190ks · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-11-04T17:04:59.780Z