Considering the following reasons for the oEmbed problem, I worked on the following and found that problem still persists. I hope this would help us to get rid of the problem.
1. Internet Speed (Tried with slower (100 kbps) and faster speed (3mbps)) [Speed is not a problem]
2. Theme Support [Theme is not a problem]
3. TinyMCE plugin (Advance and Normal) [Not a problem]
4. Hosting [Not a problem]
The point I was not able to check is version of PHP.
This is the only point I am considering for not working of the oEmbed system.
Also reading above reports, it seems that PHP version is also not a problem.
