# Error CRM Extensions - Response deserialization error

**URL:** <https://community.hubspot.com/t/error-crm-extensions-response-deserialization-error/18968>\
**Category:** APIs & Integrations\
**Tags:** timeline-and-extensions-apis\
**Created:** [February 22, 2020, 2:34am UTC](https://community.hubspot.com/t/error-crm-extensions-response-deserialization-error/18968 "2020-02-22T02:34:46Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![gmurghai](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/gmurghai/32/13631_2.png) [@gmurghai](https://community.hubspot.com/u/gmurghai)\
**Post date:** [February 22, 2020, 2:34am UTC](https://community.hubspot.com/t/error-crm-extensions-response-deserialization-error/18968/1 "2020-02-22T02:34:46Z")

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Our CRM extension was working until about 1:12PST.

We are now getting consistent “Response deserialization error”

We have not changed any code today.

This is an example of the simplest response we are sending:

{“primaryAction”:{“type”:“ACTION\_HOOK”,“httpMethod”:“POST”,“uri”:“https:\/\/domain.net\/hubspot\/action?did=1606835444&amt=&cid=&cname=”,“label”:“Create New”}}

I changed the did and the URL domain and action for this post in the message above

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**Author:** ![jac](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/jac/32/14727_2.png) [@jac](https://community.hubspot.com/u/jac)\
**Post date:** [February 22, 2020, 2:17pm UTC](https://community.hubspot.com/t/error-crm-extensions-response-deserialization-error/18968/2 "2020-02-22T14:17:38Z")

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We are getting the same message “Response deserialization error”. Our extension was working until 2/21/2020 10:51:18 AM EST.

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<div class="post-metadata">

**Author:** ![gmurghai](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/gmurghai/32/13631_2.png) [@gmurghai](https://community.hubspot.com/u/gmurghai)\
**Post date:** [February 23, 2020, 2:24am UTC](https://community.hubspot.com/t/error-crm-extensions-response-deserialization-error/18968/3 "2020-02-23T02:24:26Z")

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We just figured it out. I’m thinking there must have been a change on the Hubspot side as we didn’t make any changes over here. They perhaps got more restrictive about the return headers.

We changed the header in our response to this and it started working again:

Content-Type:

application/json

Good luck let me know if it works for you.

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<div class="post-metadata">

**Author:** ![jac](https://d10pqhm3lwygmk.cloudfront.net/user_avatar/community.hubspot.com/jac/32/14727_2.png) [@jac](https://community.hubspot.com/u/jac)\
**Post date:** [February 23, 2020, 4:59am UTC](https://community.hubspot.com/t/error-crm-extensions-response-deserialization-error/18968/4 "2020-02-23T04:59:50Z")

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Thank you. That solved my issue too.