Hello Manual Config For Iphone 
For user Softether in your IPhone you must install SSTP Connect from App Store 
You need to touch the Add icon in the right corner, then select New Profile

Protocol     sstp or softether
Description  pooyandegan
Server       s1.pooyandegan.net
Tls Server   Verification  On
Method       Password
Username     your username
Password     Your password

Add Defaualt Route (Send All Traffic)  On 
Auto Reconnect                         On 
Temporary Ipv6 Address                 On 
Switch to Wi-Fi When Avalibale         On 
Stay Connectd During Sleep             On