I recently hit a problem on my MacBook Air when trying to use Cisco WebEx. The Mac is running OS X 10.11 El Capitan.
The WebEx client installed without an issue, but when I tried to join a meeting the connection would hang at 98%. I had to use Force Quit to kill the client.
The solution to the problem was to change the proxy settings in Network Preferences. I’m not using a proxy but WebEx seems to have difficulties with the default setting.
Open “System Preferences” then select the “Network” icon.
Now select your current network connection from the left-hand panel (in my case this was Wi-Fi). Click the “Advanced…” button on the lower right of the panel.
Click the “Proxies” tab and the proxy settings are on the left. I’m not using a proxy but the default setting is “Auto Proxy Discovery”. Untick that, click “OK” and then “Apply” and WebEx would connect without any further problem.