There are security risks if the service type is configured to be Telnet or FTP. So it is suggested to configure the service type to be SSH.
Interface access control, administrator service type, and enabled service on the device determine the login method. For example, if an administrator wants to log in using HTTPS through the management interface, the management interface must enable the HTTPS access control, the administrator account must support HTTPS, and the device must enable HTTPS. For detailed configuration process, see Configuration Examples for Administrator.
If the service type of an administrator account is changed from API to FTP/SSH/Telnet/Terminal/Web or vice versa, an administrator that logs in using this account is forced out.
If the service type of an administrator account is changed among FTP/SSH/Telnet/Terminal/Web, the service type of an administrator that already logs in using this account is not changed, and the service type of an administrator that newly logs in using this account is subject to the change.
The service types of virtual system administrators can be Web, Telnet, and SSH only.
The API service is mutually exclusive with other service types. If you specify the API service type, you cannot specify other service types. The API service administrator must be in Level 15.