You will be able to get inside using an access code or card, as in the usual intercom system.

If you do not receive a call with a confirmation code, click “Send again” and instead of a call you will receive an SMS with a code.

Calls may not be received due to your phone's security settings. Allow the app to run in the background and disable battery saving mode. This will not affect the operation of your phone. Different phones have different settings, you need to add an application HomeiD to exceptions to send PUSH notifications, work in the background, access the camera, microphone, on top of all windows.