Slack & Whatsapp desktop apps cant connect 2 Internet Connection

I am facing issues with these three desktop apps (Slack, Whatsapp, Upwork) which require internet to run. All three apps show that I am not connected to the internet although I am connected and I can use internet on browsers and other apps. These apps just open up and cant connect to the internet. Something is blocking them to use the internet. I have not set up any proxy settings and I use broadband as well as wireless dongle for internet. In both internet, these apps dont work.

I have tried various things like disabling the Windows Firewall, Disabled the antivirus, reinstalled all three apps but nothing worked. If someone is good at networking trouble shooting, please guide me.

Please dont tell me that my phone should be connected to internet for the whatsapp. I know that and its not about syncing with the phone. I can use the web browsed based whatsapp web and my issue is not regarding whatsapp only. Slack and Upwork apps too dont work.