I want to send a static HTML error page when a user tries to reload the callback route of Spotify's OAuth flow. I use Nodejs for my backend and send the static HTML file using res.sendFile(). There is a GIF in the html which is visible when run locally but does not get rendered in the deployment. The site is deployed on cyclic.sh. The code of the HTML is as follows:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Spotube</title>
<link rel="stylesheet" href="style.css">
</head>
<body>
<div class="error-container">
<img src="totoro.gif" alt="Error image" class="error-image">
<h3>Do not refresh this page or you'll have to go back and login again </h3>
</div>
</body>
</html>
Also Failed to load resource: the server responded with a status of 500 () pops up in the Chrome Developer Console but when I look at the Deployment Logs in Cyclic, I find these
The files are also stored at the same level so I can't understand where I'm going wrong 
The result I want (which I get locally)
The result I get in my deployment
