Why the favicon links n my index.html file are not working?

I've seen other links but the truth is my favicon is still not working. Sometimes I do some changes in the code, and the favicon of my portfolio page is only seen once. It stops working once I load the site for the second time.

I went to the site favicon.io and created my own favicon. Like instructed, saved in the root directory of my repository and copy/pasted the code.

<link rel="apple-touch-icon" sizes="180x180" href="/apple-touch-icon.png">
<link rel="icon" type="image/png" sizes="32x32" href="/favicon-32x32.png">
<link rel="icon" type="image/png" sizes="16x16" href="/favicon-16x16.png">  
<link rel="manifest" href="/site.webmanifest">

However, those links are not working. Can anyone please advise? Is there any change I need to do?