Hi there, as stated in the subject:
stefan:~/ $ curl -d 'password=test%test' https://www.arcgis.com/sharing/rest/generateToken
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>HTTP ERROR 500</title>
<body>
<h3>HTTP ERROR 500</h3>
<p>Internal Server Error<p>
</body>
</head>
</html>
</body>
</head>
</html>
Does not seem like expected behaviour. I will make sure the affected user does not have a % sign in their password.