There are multiple reasons why iCall can be unsuccessful in placing telephone calls.

First, make sure that you have the most up-to-date copy of iCall. If your version is outdated, visit the download page to download the latest version.

Next, check to make sure that iCall is not being blocked by Microsoft Windows' firewall. Open your Control Panel and double-click on "Windows Firewall." In the window which appears, select the "Exceptions" tab. In the list, make sure that there is a checked entry labeled "iCall." If there is not, click the "Add Program" button. In the window which appears, select "iCall Internet Phone" and click "OK." Click "OK" multiple times to return to the Control Panel.

If iCall still is unsuccessful in placing calls, you may have to manually create exceptions for certain ports. Open your Control Panel and double-click on the "Windows Firewall" icon. Select the "Exceptions" tab and click the "Add Port" button. In the window which appears, select the "UDP" option box. Enter "iCall Port" in the "Name" textbox and enter "4255" in the "Port Number" textbox. In the window which appears, select the "UDP" option box. Enter "iCall Port" in the "Name" textbox and enter "9000" in the "Port Number" textbox. Click "OK" multiple times until you return to the Control Panel.

Third party firewall applications may also be installed on your computer and may be blocking your ability to make calls.

Additionally, while iCall does work with *most* NAT enabled routers, you should make sure that your router if it is NAT enabled is properly configured to route calls on port 4255 AND port 9000 to your computer.

Finally, while it is quite rare, some ISP's have been known to block VoIP packets to try and force you to use their overpriced telephone service. If your ISP is doing this we encourage you to contact your current ISP for a resolution or switch to another ISP.