Hi Steven,
Thanks for providing me a detailed instruction, Now this problem of popup ads have been resolved..
I simply installed a ssl certificate and my problem is gone, but I am not able to figure out what was causing me this problem.

Hello Ranjan,

It appears that you are using the Firefox browser.

In previous encounters with similar issues, it has proven to work if you ....

• remove the complete Firefox profile ( saving your bookmarks first, extensions can be problematic but can be got at from source again - to eliminate the issue.)

• allow Firefox to build a new profile on relaunch

• test for the issue again.

You can also test the issue with a different browser to see if the problem is unique to Firefox or is cross browser.

It does appear to be some sort of malware hook which could attach itself in the profile, so rebuilding a fresh profile could well get rid of it also.

It is just a thought and no guarantee that it will solve it but worth a try, along with the other suggestion made also.

Thanks ~Z~ Man and Steven for writing me,
I will try both the solutions and let you know which method worked for me.

Hi Ranjan!

Do you have shell access to our server?

• If so, login to your machine, cd to your ossn installation directory and run
  grep -Rni "allashail.club" .
  This way all sources which are calling that advertiser will be listed and you can remove the code.
• If not, copy the current Ossn installation by FTP to your local PC and do the search there as explained in https://www.opensource-socialnetwork.org/wiki/view/1137/how-to-find-something-a-word-pattern-in-the-source-code (Case A)

It has nothing to do with OSSN...

It is a form of malware and there are various sites that can give you suggestions as to how to remove it...

Google is your friend...