IIS 10 brings support for wildcard domains. However WCF does not support it!
We had a WCF service hosted on IIS (in an Azure CloudService to be more specific) and this website had hostname like "lille.monsite.com ; paris.monsite.com ; lyon.monsite.com …".

Here is the original configuration (was working as expected)
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Having a wildcard SSL certificate *.monsite.com, we adapted the configuration to allow the website to respond to *.monsite.com and removed old hostnames. Doing this, the WCF service fails with an HTTP 500 error !
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To make it simple : our service cannot load anymore, more precisely it cannot load its' binding configuration.

After some research, we found that WCF does not support host header of wildcard type : https://blogs.msdn.microsoft.com/dsnotes/2017/07/07/wcf-support-for-wild-card-host-header-at-iis-10-and-above/

To fix the problem : we added a fake header "localhost" at top of the header list. The trick here is to allow the service to load using this localhost header. Still, it will nicely respond to queries like "mycity.monsite.com"! Warning, this “non wildcard header” has to be first in the list to make the WCF service to load properly!

Here is the configuration :
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and the result :

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