Some applications won't connect to the internet via 3G after rooting my phone I have initially a Motorola moto g xt1039 with Android 4.4.4

I have rooted the phone by following this guide.

The phone works normal, I am able to connect to the internet via Wi-Fi.

Some applications such as Google Play and Twitter are able to connect since I can install apps and refresh my Twitter feed by using the 3G connection.

I've been also able to ping to 8.8.8.8 and to www.google.com by using the terminal emulator.

Furthermore, sharing the 3G connection through Wi-Fi works as well, I've been able to use the shared connection from my Laptop PC.

The very confusing problem is that some applications such as chrome, firefox, Gmail, and Youtube are unable to connect when using the 3G connection.

These applications start, keep loading for a while and then show an error message, usually "unable to load" or "connection timeout".

What is going on here, how to troubleshoot this issue?
The problem was that a bogus proxy was set for the Mobile Data Connection I was using.

Removing the bogus proxy configuration solved the issue!

Here is a guide to Mobile data connection proxy setting.