This is an SSTP connection error. If you are setting up SSTP on your Windows server, after installing a certificate you will see the error code when trying to connect as a client.
Tip: Solution if The remote host closed the connection.
The problem may be with the certificate during the authentication process. Check the machine certificate or server certificate. To find more information about the certificate, run netsh http show ssl.
TipFor more information, please see: How to fix Connection error #0x80072746