# C# SDK - Auth Service callback isn't invoked

**URL:** <https://devforum.zoom.us/t/c-sdk-auth-service-callback-isnt-invoked/1097>\
**Category:** Windows\
**Created:** [March 17, 2018, 9:55pm UTC](https://devforum.zoom.us/t/c-sdk-auth-service-callback-isnt-invoked/1097 "2018-03-17T21:55:41Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![24x7\_LIVE](https://avatars.discourse-cdn.com/v4/letter/2/c2a13f/32.png) [@24x7\_LIVE](https://devforum.zoom.us/u/24x7_LIVE)\
**Post date:** [March 17, 2018, 9:55pm UTC](https://devforum.zoom.us/t/c-sdk-auth-service-callback-isnt-invoked/1097/1 "2018-03-17T21:55:41Z")

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We intend to integrate Zoom in our Windows .Net application. We have been trying to run the C++ and C# demo apps. While the C++ demo app (downloaded from GitHub) runs just fine and behaves as expected, the C# demo app&nbsp;(again downloaded from GitHub with no changes made) runs but the callback for auth service (i.e. onAuthenticationReturn) never gets invoked and therefore we aren’t able to proceed further.

We ensured we are using the correct SDK credentials by using them from the C++ app and have followed all the instructions here:  
[https://developer.zoom.us/docs/windows/c-wrapper-introduction/](https://developer.zoom.us/docs/windows/c-wrapper-introduction/)

What needs to be done to be able to run the&nbsp;C# demo app other than set it up as in the link above?

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**Author:** ![dats\_liao](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/dats_liao/32/464_2.png) [@dats\_liao](https://devforum.zoom.us/u/dats_liao)\
**Post date:** [March 19, 2018, 9:50am UTC](https://devforum.zoom.us/t/c-sdk-auth-service-callback-isnt-invoked/1097/2 "2018-03-19T09:50:36Z")

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hi,

could you to double check your&nbsp;executable file folder to ensure all of the sdk DLLs in your “debug” folder. if yes, please help to check the result of the sdk init api.&nbsp;

thanks&nbsp;

Regards

Dats

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<div class="post-metadata">

**Author:** ![24x7\_LIVE](https://avatars.discourse-cdn.com/v4/letter/2/c2a13f/32.png) [@24x7\_LIVE](https://devforum.zoom.us/u/24x7_LIVE)\
**Post date:** [March 21, 2018, 8:10pm UTC](https://devforum.zoom.us/t/c-sdk-auth-service-callback-isnt-invoked/1097/3 "2018-03-21T20:10:17Z")

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Hi Dats, thanks for your response. Indeed, it was issue with sdk dlls not being present in “Debug” folder. Thanks a lot for your help.

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**Author:** ![tommy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/tommy/32/72769_2.png) [@tommy](https://devforum.zoom.us/u/tommy)\
**Post date:** [September 20, 2021, 8:54pm UTC](https://devforum.zoom.us/t/c-sdk-auth-service-callback-isnt-invoked/1097/4 "2021-09-20T20:54:27Z")

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Closing as solved.

-Tommy

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<div class="post-metadata">

**Author:** ![tommy](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/tommy/32/72769_2.png) [@tommy](https://devforum.zoom.us/u/tommy)\
**Post date:** [September 20, 2021, 8:54pm UTC](https://devforum.zoom.us/t/c-sdk-auth-service-callback-isnt-invoked/1097/5 "2021-09-20T20:54:30Z")

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Closed on September 20, 2021, 8:54pm UTC