When I am trying to use Azure openai chat playground, I got an error

@GUO Ranfei (RBCC/BDO1) Welcome to Microsoft Q&A Forum, Thank you for posting your query here!
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Plan 1:
Could you please check the Networking setting and confirm if you have enabled the access from selected Network ? If Yes, Please try changing it to All Networks and check if that resolves the issue.

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Plan 2:
If you want to use the Virtual Network, follow the steps mentioned here to configure it correctly.
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Plan 3:
If you have firewall rules enabled, grant access to an internet IP range, enter the IP address or .address range (in CIDR format). Only valid public IP (nonreserved) addresses are accepted.

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Plan 4:
Please check if you have any proxy / firewall within your corporate network ? If yes, ensure that the *https://${customDomainName}.openai.azure.com*endpoint is whitelisted in it.
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Plan 5:
If you are using the Private endpoint connections as shown below, then follow the steps mentioned here.

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Hope this helps. If you have any follow-up questions, please let me know. I would be happy to help.

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