Product:
Cognos Controller 10.4.1 web
Microsoft Windows Server 2016

Problem:
Change to use DNS alias to the cognos controller server, and now can not login to the Controller Web,
“Server is not reachable or still initializing, please refresh the page in a few seconds”
If you surf direct to servername, then controller web works, it is only with dns alias that give the error.

Solution:
You need to change to the DNS alias in the file for Controller Web front end.
Stop the IBM Cognos Controller Web UI service
Start NOTEPAD as administrator
Open file D:\Program Files\ibm\cognos\ccr_64\frontend\config.js
Change the server name at line 25 to be the dns alias

“expressJs”: {
“host”: “dnsalias.domain.com”, //interface used by Controller Web UI Service
“port”: “9080”, //port used by Controller Web UI Service

Save the file.
Start the IBM Cognos Controller Web UI service

Test to surf to http://dnsalias.domain.com:9080/ to see if Controller Web works.

Now to surf to server name, should not work instead.

More Information:
https://www.ibm.com/support/pages/server-not-reachable-or-still-initializing-please-refresh-page-few-seconds-error-launching-controller-web-caused-incorrect-tcp-port-inside-serverxml
https://render-prd-trops.events.ibm.com/support/pages/troubleshooting-server-not-reachable-or-still-initializing-please-refresh-page-few-seconds-error-launching-controller-web
https://www.ibm.com/support/knowledgecenter/en/SS9S6B_10.4.1/com.ibm.swg.ba.cognos.ctrl_inst.doc/t_contrweb_configure.html

In cmplst.txt you will find this version for controller 10.4.1:

LICENSE_CONTROLLER_version=LICENSE_CONTROLLER-AW64-ML-RTM-10.4.1100.1-0
LICENSE_CONTROLLER_name=IBM Cognos 8 License
SWTAG_CONTROLLER_version=SWTAG_CONTROLLER-AW64-ML-RTM-10.4.1.1-0
SWTAG_CONTROLLER_name=SWTAG CONTROLLER
CONTRL_version=CCR-AW64-ML-RTM-10.4.1100.133-0
CONTRL_name=IBM Cognos Controller