I am on android 4.4.2. Using Orbot + Orfox. I can connect the Tor network and browse webpages on Orfox when I am connected to a Wi-Fi. But whenever I turn-off wi-fi and try Mobile data, the pages on Orfox does not load. Here, How to make Tor work using mobile data?, they mention that mobile carriers may block access to Tor. And it is suggested that I should use bridges available. How can I do that? Checking "Use Bridges" option on android app does not resolve the issue (I haven't entered any IP address and port of bridges, since I do not know how to do it.)
1- Get bridges:
Enter bridges.torproject.org on your mobile browser. On the page opened, click on "Get Bridges" option. Scroll down to the "Advanced Options" box, and select "obfs4" on "Do you need a Pluggable Transport?". I didn't meddle with the "Do you need IPv6 Addresses?" opiton. By default, I found the "Advanced Options" box already selected as "obfs4" and "Do you need IPv6 Addresses?" box unchecked. Then, click on get bridges. Do the captcha. Get the bridge IP's and ports and other information.
2- Apply bridge settings on Orbot:
On mobile, click Orbot app. Get to settings in the app. Scroll down to the "Bridges" header. Check "Use Bridges" option. Then go back to your mobile browser and copy all the line that bridges.torproject.org gives you as bridge information. Copy all the line. Then, head back to the Orbot app options, and click "Bridges" option. Paste the copied information in the pop-up. Click "OK".
3- Restart your mobile device:
Now, at first, I wasn't aware that I needed to restart my mobile device. So, the changes didn't have any effect. But, after restarting my mobile device, the changes seem to get applied. Now, I can connect to the internet through Tor network on mobile data.