Hello @Alok Aswal ,
Thank you for posting your query on Microsoft Q&A. The issue seems to be with your "Metadata" URL.
As per https://learn.microsoft.com/en-us/azure/active-directory-b2c/id-token-hint#metadata, METADATA is "A URL that points to a token issuer configuration document, which is also known as an OpenID well-known configuration endpoint" i.e. your relying party discovery endpoint. Kindly have this replaced with it.
For example, in my case FB is relying party so, the meta data URL could be found from the Signup-Signin:
Please do let me know if you have any further queries in the comments section.
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