Symptom
When running the FME Flow (formerly Server) installer, an error message displays:
“The specified port seems to be in use. It is recommended that you change the port to one that is open.”
Cause
This can occur when a program is using the port you are trying to connect on, likely port 80.
Resolution
Disable services that are using FME Flow's port, likely port 80. These may include Internet Information Services (IIS), World Wide Web Publishing Service, Windows Remote Management and Skype.
Another option is to use an alternative port. Port 8080 is common alternative for web services. During the installation of FME Flow you are prompted to provide a different port. Port 80 is the default, however this is where you can set the port value to 8080 when it is not possible to disable IIS service or WWW Publishing Service that use port 80.
This means to access FME Flow Web UI you must include the port value in the URL. ex: http://localhost:8080/fmeserver
Some other customers have reported success using port 8088 or 8888 for the Web App Server.