IOS Bundle Signing Visual Studio Windows

I am new to xamarin IOS and I couldn't complete automatic provisioning(via IOS Bundle Signing).

I am getting the following error, not sure exactly why this error comes out. It says the App ID is not available. But I also don't see it in the developer portal.

The exact error is "An App ID with Identifier 'com.xxxxx.xx' is not available. Please enter a different string."

Can someone help me to fix this out?
IOS Bundle Signing Visual Studio Windows
 
 
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