Thank you joe_intel, I already insert this entry in Windows Firewall but it did not solve the pb.
But finally I found why.
Sorry for my English, I am french speaking and I'll try to translate the parameters I had to change:
In Windows Firewall if I click on "Activate or Deactivate Windows Firewall", I had to uncheck
"block all entries connections included those from authorised applications list".
And this for Private and Public networks.
And this made the trick. Windows Firewall is activated and Miracast is working.
I dont know why these two parameters were checked. All other PC's W7, W8, W8.1
I looked at have this options unchecked.
Thank you for answering, you guide me to solution.
Best regards.
Eric