error - An error occurred: Fleet App Server unavailable.

Symptom

Trying to change the internal IP address for the external IP address into Fleet App Server URL - http://xx.xx.xxx.xx:80/GpsGateServer and keep getting an error -
An error occurred: Fleet App Server unavailable. I have another GpsGate server and this works with the external IP address. I have enabled the mobile login.


Possible Cause:

  • The working server http://YY.YY.YY.YY/GpsGateserver/ is accessible from the internet
  • The failing server http://XX.XX.XX.XX/GpsGateserver/ is not at all accessible from the internet.

Solution:
Some tips:

  • Check that windows firewall allows external access on TCP port 80.

  • Check that any routing hardware or software between the server and the public network port forwards port 80 correctly to the server's internal IP address.