How to add a custom domain to your account?

Hello,

As I recall, you need to work with Zoom support to do this. I had to submit documentation proving I owned the domains. Do you have an account rep?  If not, you should at least open a support ticket.

https://support.zoom.us/hc/en-us/requests/new 

Prerequisites for associated domains

• Business, Enterprise, or Education account
• Account owner or admin privileges
• A custom domain owned by your organization
  Note: Some domains, such as @gmail.com and @outlook.com, cannot be used.

https://support.zoom.us/hc/en-us/articles/203395207-Getting-started-with-associated-domains 

https://support.zoom.us/hc/en-us/articles/4405656980109 

Regards

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