If you have linked a certificate to a port to encrypt communication between the apps, you can check in the d.ecs http gateway administration how the apps register with the d.ecs http gateway app.
This is how it works
Open the d.ecs http gateway app administration with https://<Computername>:4280/httpgateway/ui or select the d.ecs http gateway admin entry in the Windows start menu in the d.velop program group.
In the Apps area, click the relevant app.
Click the app to view the app's properties.
Under Destination URL, check whether the URL begins with HTTPS.
See also: Linking the certificate and port for inter-app communication with HTTPS