thank-you for your answer.
My network connection is good, if I use a manjaro native “Fortinet SSL VPN” backup connection, it works. When I use cisco anyconnect client, I have the error.
If I try with a manjaro native “Cisco AnyConnect or OpenConnect” profile I obtain an error too :
Got HTTP response: HTTP/1.1 404 Not Found
Not a good idea to use Manjaro or any other rolling release distro if your work depends on Cisco Anyconnect. They only support Redhat and Ubuntu, and package updates in a rolling release distro will break it. E.g.