Please give me a solution to this if possible. Image showing white outlines when zoomed.
Dave Nelson's comment seems to be right: The image is overly sharpened, creating a halo. You do not see it when zoomed out simply because it becomes too small; it is still there.
Look at Dave Nelson's comment for a link to a detailed explanation on digital sharpening.
Edit: Smartphones and even DSLRs typically add digital sharpening themselves. Maybe you have access to the settings of that shaprening.