Server is not reachable or still initializing

Product:
Cognos Controller Web 10.4.2
Microsoft Windows 2019 server

Problem:
User browse to Controller web and get a message

Server is not reachable or still initializing, please refresh the page in a few seconds

Possible Solution:

Depending on the URL you enter in your Internet Explorer you will succeed or not.

This give above error

http://servername:9080/#!/Login

If you enter the FQDN like this it will work

http://servername.domain.com:9080/#!/Login

The error can also be that you are to fast, the controller web will need some time to start up.

More information:

https://www.ibm.com/support/knowledgecenter/SS9S6B_10.4.2/com.ibm.swg.ba.cognos.ctrl_web_ug.doc/c_web_workflow.html

https://www.ibm.com/support/pages/link-planning-analytics-not-configured-when-configure-controller-web-connect-tm1-pa-web-caused-apar-ph19087