Hello,
Actually you should open the HTTP service connection, per SAP note 592085. When opening this connection, you can define an URL, which can be http:// or https://.
Remember that you need to put in the saprouter the actual HTTPS port, as a wildcard (*) cannot be used. You can check in your ICM for the actual HTTPS port.
If this remote connection cannot be opened, then the GoToAssist support session is a possibility - as long as you and the support staff schedule a meeting, so you can share your screen.
Kind regards,
Cris