A year ago, Rally's hints were helpful, today they're obvioulsly not. Thus, we can only assume that your site is some way different- - a more recent Ossn, another theme ... no idea...
So please provide more details as explained in
https://www.opensource-socialnetwork.org/wiki/view/1101/how-to-report-a-bug-error

Hi, I appreciate this thread is over a year old but I have installed the v1.1 component and still experiencing the same problem as described. Changing the default.php file does not seem to correct it and although it is not only a very good component and something I particularly want to use, it simply does not work in its correct form and I have to disable it.

Has there been any progress on this or an update that I have missed?

Thanks

Thanks a ton Rally......this community rocks......have a good day

Rally,
Thank you... thank you... thank you.
I can't say enough about how great the OSSN community is. That is exactly what I wanted.

Try this:

.topbar {
    position: fixed;
    width: 100%;
    z-index: 999;
}

.ossn-page-container .ossn-inner-page {
    margin-top: 50px;
}

I tried (position: relative;) changing relative to fixed; , though the Top Bar was fixed to the top and the news feed were scrolling underneath it ,but messed up the margins on the right side both on mobile and desktop. It will be great if Arsalan can tel us how to make the top bar fixed to the top. Thanks.

I would like the top bar to stay pinned to the top as everything else scrolls underneath it. This way when a user has scrolled down if they want to return to the top they will have the site title there to click on and return to the top. Also, so they will always have the notification icons always in view.

You mean the sidebar should move with the page? can u explain more?