Preview PDF search issue

Hi everyone ,

From the past two weeks I have noticed that when I open PDFs on Preview and search for a particular word, the app does not display or highlight the searched word on the PDF. Usually, when I search for a word - the preview app showed number of entries found on the word, the side bar displayed pages with text in bold, and the word was highlighted in yellow as I scrolled the PDF. Lately none of this is happening. The sidebar displays only page number but does not locate the text that I am searching for... the searched text is not highlighted as I scroll the PDF too.. Another thing is that after I enter a text in the search box and press enter, I hear the sound as if the page was blocked or stuck. Previously, when the preview was working alright - pressing enter would take me to the next word on the PDF located by the search..

Any idea or solution for this?