# Invalid Retry-After header on create registrant API

**URL:** <https://devforum.zoom.us/t/invalid-retry-after-header-on-create-registrant-api/57731>\
**Category:** API and Webhooks\
**Created:** [September 20, 2021, 7:34pm UTC](https://devforum.zoom.us/t/invalid-retry-after-header-on-create-registrant-api/57731 "2021-09-20T19:34:24Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![jared\_mobilize](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/jared_mobilize/32/31217_2.png) [@jared\_mobilize](https://devforum.zoom.us/u/jared_mobilize)\
**Post date:** [September 20, 2021, 7:34pm UTC](https://devforum.zoom.us/t/invalid-retry-after-header-on-create-registrant-api/57731/1 "2021-09-20T19:34:24Z")

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Hi, starting at Sep 18, 2021 2:34:03 AM UTC we started seeing responses to the create registrant API (`POST https://api.zoom.us/v2/webinars/<id>/registrants`) respond with HTTP status 429 (which is expected, our app handles it) but with an invalid `Retry-After` header that the Python `requests` library does not know how to interpret (we are seeing ISO8601 timestamps like `2021-09-21T00:00:00Z` from the API, instead of HTML dates or a count of seconds, which per MDN are the expected formats for Retry-After values: [Retry-After - HTTP | MDN](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After))

Was there a change that went out around then to modify the format of Retry-After headers, and if so, is it possible to fix it to be in compliance with the expected date formats? This is making our Zoom integration basically unusable.

Thanks,  
Jared

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**Author:** ![will.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/will.zoom/32/14417_2.png) [@will.zoom](https://devforum.zoom.us/u/will.zoom)\
**Post date:** [September 24, 2021, 2:19pm UTC](https://devforum.zoom.us/t/invalid-retry-after-header-on-create-registrant-api/57731/2 "2021-09-24T14:19:12Z")

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Hey @jared_mobilize,

Thanks for reaching out about this. Is it possible to share the full header for a recent request with us at [developersupport@zoom.us](mailto:developersupport@zoom.us) so that we can take a closer look at this?

Thanks!  
Will

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**Author:** ![jared\_mobilize](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/jared_mobilize/32/31217_2.png) [@jared\_mobilize](https://devforum.zoom.us/u/jared_mobilize)\
**Post date:** [September 24, 2021, 5:00pm UTC](https://devforum.zoom.us/t/invalid-retry-after-header-on-create-registrant-api/57731/3 "2021-09-24T17:00:43Z")

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> [@will.zoom](#):
>
> [developersupport@zoom.us](mailto:developersupport@zoom.us)

Hi @will.zoom, just sent some more details over to that email address. Thanks for your response!

Jared

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**Author:** ![will.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/will.zoom/32/14417_2.png) [@will.zoom](https://devforum.zoom.us/u/will.zoom)\
**Post date:** [September 27, 2021, 1:08pm UTC](https://devforum.zoom.us/t/invalid-retry-after-header-on-create-registrant-api/57731/4 "2021-09-27T13:08:38Z")

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Hey @jared_mobilize,

Thanks for sending those details over. I’m working with our Engineering team on this and will follow up with you shortly via email.

Thanks,  
Will

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**Author:** ![system](https://us1.discourse-cdn.com/flex016/uploads/zoomdeveloper/original/3X/6/1/614bdd549b610bbaa46ff934617683a02bdaa03c.png) [@system](https://devforum.zoom.us/u/system)\
**Post date:** [October 27, 2021, 11:08pm UTC](https://devforum.zoom.us/t/invalid-retry-after-header-on-create-registrant-api/57731/5 "2021-10-27T23:08:51Z")

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Closed on October 27, 2021, 11:08pm UTC

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