You can try to Reset the Network Connection and see if that helps.
The command will remove all your existing connections, so we recommend you create a system restore point before executing this command.
-Open PowerShell in admin mode.
-In the PowerShell console, type in the command below and hit Enter to restart all network adapters and remove MUX objects.
-Exit PowerShell when the command executes.
-Now, open Virtual Switch Manager in Hyper-V Manager and try to create an external switch and see if the error reoccurs
Hope this resolves your Query !!
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