Hi @Pramod Ashokkumar ,
You need to be logged in with a Global Admin account in order to save the settings and the error you described could indicate that the permissions are missing.
Allow or block invites to specific organizations - Microsoft Entra External ID | Microsoft Learn
If you are still seeing this issue while logged in with the correct permissions, let me know and I will file a bug. If you are able to provide HAR traces for me, you can send them to me at AzCommunity@microsoft.com ("Attn: Marilee Turscak"). There was a recent incident related to this issue, but it was resolved.
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