# Can't join webinar as panelist with error when using zoom custom ui

**URL:** <https://devforum.zoom.us/t/cant-join-webinar-as-panelist-with-error-when-using-zoom-custom-ui/67880>\
**Category:** Windows\
**Tags:** webinar\
**Created:** [April 21, 2022, 11:18am UTC](https://devforum.zoom.us/t/cant-join-webinar-as-panelist-with-error-when-using-zoom-custom-ui/67880 "2022-04-21T11:18:08Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Miyamoto](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/miyamoto/32/36997_2.png) [@Miyamoto](https://devforum.zoom.us/u/Miyamoto)\
**Post date:** [April 21, 2022, 11:18am UTC](https://devforum.zoom.us/t/cant-join-webinar-as-panelist-with-error-when-using-zoom-custom-ui/67880/1 "2022-04-21T11:18:08Z")

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**Description**  
When I tried to join webinar as panelist with zoom custom ui, I got error “Failed to join meeting. got error code= 21” ( MeetingFailCode’s value 21 is MEETING\_FAIL\_REGISTERWEBINAR\_PANELISTREGISTER).  
What does this error mean, and how can I join webinar as panelist?

**Which Windows Meeting SDK version?**  
v5.9.1.2625

**To Reproduce(If applicable)**  
Steps to reproduce the behavior:

1. Open login ui
2. Input Meeting ID and Meeting Code
3. Click Join
4. Input registered mail address and webinar name
5. Gets error message

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**Author:** ![jon.zoom](https://sea2.discourse-cdn.com/flex016/user_avatar/devforum.zoom.us/jon.zoom/32/13495_2.png) [@jon.zoom](https://devforum.zoom.us/u/jon.zoom)\
**Post date:** [April 22, 2022, 8:52pm UTC](https://devforum.zoom.us/t/cant-join-webinar-as-panelist-with-error-when-using-zoom-custom-ui/67880/2 "2022-04-22T20:52:10Z")

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Hi @Miyamoto,

Can you please provide a code snippet showing how you are trying to join the webinar?

Thanks!

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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:** [May 23, 2022, 6:52am UTC](https://devforum.zoom.us/t/cant-join-webinar-as-panelist-with-error-when-using-zoom-custom-ui/67880/3 "2022-05-23T06:52:25Z")

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Closed on May 23, 2022, 6:52am UTC

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