Is your Windows computer a tablet by chance? If it is, try this to see if it helps resolve the issue:
1. In the windows search field type Windows Powershell and run it as admin
2. At the powershell prompt paste this command without the quotes and hit enter, "Set-ProcessMitigation -Name CiscoCollabHost.exe -Disable UserShadowStack"
3. Try to open the Webex app
If it doesn't work, open a ticket with Cisco TAC.