The error appears when the ELIAS frontend (Scout) cannot reach the backend service. Several environment‑dependent factors can cause this:

• The config.json (or config.js) file contains incorrect protocol or port values.

• The protocol (http vs. https) does not match the actual server configuration.

• When ELIAS is installed using IIS, IIS enforces HTTPS on port 443. In this case, the configuration must use https and port 443.

• When IIS is not used, ELIAS typically runs on HTTP using port 80 or a manually configured custom port.

• A common scenario: config.json is set to port 443 even though encryption is not used, causing the frontend to attempt an HTTPS connection that fails.

• The browser URL and the configuration file must match exactly (same protocol and port).

Configuration file location: C:\Program Files\Unicon\Scout\ELIAS\config.json

The frontend cannot connect to the ELIAS backend because the protocol or port in config.json does not match the actual server setup. This usually happens when:

• IIS uses HTTPS on port 443, but the config is set to HTTP or port 80.

• IIS is not used, but the config is still set to HTTPS/443 instead of HTTP/80.

• The browser URL and the config file use different protocol/port combinations.

1. Open the config.json file located in C:\Program Files\Unicon\Scout\ELIAS.

2. Verify the following values:

   • "protocol": "http" or "https"

   • "port": 80, "443", or the custom port used in the environment

3. Adjust the configuration to match the actual deployment:

   • If IIS is used -> set protocol to https and port to 443.

   • If IIS is not used -> set protocol to http and port to 80 (or the manually configured port).

4. Ensure the browser URL matches the configuration (e.g., http://server:80/elias instead of https://server/elias).

5. Restart the ELIAS service or the IIS site, depending on the installation method.

6. Reopen ELIAS in the browser and confirm that the connection is established successfully.

Users may encounter the message “Waiting for connection to ELIAS service” when accessing the ELIAS web interface. This issue typically occurs when the frontend cannot establish a connection with the backend service due to incorrect protocol or port configuration, or due to mismatched IIS and certificate settings.

• Citrix documentation (Windows installation, section 6): https://docs.citrix.com/en-us/unicon-elux-scout/short_guides/installation/install_elias18/elias18_install_win

• Port 443 is used exclusively when ELIAS is hosted through IIS.

• When using HTTP (no encryption), port 80 is typically used.

• If a custom port is configured, ensure firewall rules and any reverse proxy settings allow traffic.