Not making any workable version from few sprints

What is stopping us from delivering a potentially releasable increment every Sprint?

This sounds like a perfect topic for your Retrospective. I would bring it to the entire Scrum team and see if you can figure it out. Take a step back and figure out how to make one potentially releasable increment, and go from there.

What sort of Sprint Goals are being agreed with the Product Owner if they don't demand a potentially releasable increment?

It sounds like a refinement problem for starters:

Title: Page X Browser Consistency
Story: As a Page X user, I want my experience to be consistent, so that I can seamlessly perform the same tasks on a variety of platforms

What was the verification criteria for your story?
Given windows 7, 10 with default font sizes
Given the browsers Firefox v44+, Chrome v28+ with default font sizes
Given resolutions 400x800-1920x1080
When I visit page X
Then the page is formatted identically for all Browsers

Nothing in this story describes behavior of the page, just layout. By delivering that at the end of the sprint, you give stakeholders and customers time to decide if that layout suits their needs. That is something of value.

Maybe that story is two big? It may need to be split into further stories. You need to understand your goal.

Once the layout is approved, then you can create an interface to store that information into a database. The real database is then inconsequential, so long as there exists a facade to that database that implements that interface, in which case for prototyping you could write a flat file or an in memory structure to demonstrate the behavior of the page while the real database work is refined/underway.

Thank you Anon.

so it doesn't matter whether it is usable by customer or not as along as we meet the deliverable. Because just launching UI may not bring any business values to customer?.

Thanks
Senthil