This is what the pop-up is displaying,
"Sorry, we were unable to connect to your backend. This may be due to a restriction in your location. Please visit the link below for more information.https://research.google.com/colaboratory/faq.html"

Even after changing my browser from chrome to edge, and opening the colab in Incognito mode, I am still facing this issue. Also, tried opening a new notebook, in case if this issue is in a particular notebook. Additionally, I tried clearing all the colab cookies multiple times.

In the "Resources" Section, it is displaying:
"You currently have zero compute units available. Resources offered free of charge are not guaranteed. Purchase more units."

What does this mean, isn't colab free to use for everyone?

I used both Chrome and Edge