Cannot open ADFS login page while testing connection or trying to log in with an error err_connection_reset

Cannot open ADFS login page while testing connection or trying to log in with an error "err_connection_reset"

Issue:
When trying to connect to the fresh installation of ADFS from the CPM, you may receive an error message "err_connection_reset".
When this issue occurs, no error or warning message appear in the CPM log files.

Description:
This issue may happen because of several reasons:
  1. IIS on the the machine where ADFS is running is not configured to allow connections via HTTPS on 443 port.
  2. IIS is not running.
  3. One of the firewalls/security groups between CPM and ADFS is blocking 443 port.
Resolution:
  1. Check if IIS allows HTTPS traffic:
    1. Open 'Server Manager' on the machine where ADFS hosted.
    2. Select 'Tools'>'Internet Information Services (IIS) Manager'.
    3. In the opened window, select your server then go to 'Sites'>'Default Web Site' and click 'Bindings'.
    4. Verify if HTTPS binding is configured. If it is, please check if SSL certificate assigned to this binding and click OK. If it's not, click 'Add...'
    5. In the 'Add Site Binding' window, select 'HTTPS' type and assign SSL certificate and click 'OK' and 'Close'.
    6. Check connection from the CPM.
  2. Check if IIS is installed on the machine where ADFS is hosted or if it's stopped.
  3. Check your firewalls/security groups if they allow connection over port 443.