Issue
I had to remove the SSL certificate from a Private Space app and the app now refuses to accept requests through HTTPS:
$ curl -v https://(app-name).herokuapp.com/
* connect to the IP address port 443 failed: Connection refused
* Failed to connect to (app-name).herokuapp.com port 443: Connection refused
* Closing connection 0
curl: (7) Failed to connect to (app-name).herokuapp.com port 443: Connection refused
I need to have access to the default domain through HTTPS restored.
Resolution
There is actually a procedure on Heroku API missing when an SSL server certificate is removed from a Private Space app. That has caused the app to receive network connections at port 443. Our engineers are aware of the problem and are working for a fix.
In the meantime, the problem maybe able to be fixed for a publicly accessible app with enabling ACM heroku certs:auto:enable and disabling it again heroku certs:auto:disable.
For an app in a Private Space with Trusted IP ranges enabled or Internal Routing enabled, we'd need to fix the problem on our side. Please file a support ticket and let us know the name of the app.