I was able to replicate this too. running the newest version 1.21.4. No mods no plugin system pure vanilla and i get:
whitelist add hypersmc
[15:01:33] [Server thread/ERROR]: Got an error with a html body connecting to https://api.minecraftservices.com/minecraft/profile/lookup/bulk/byname: <html>
<head><title>403 Forbidden</title></head>
<body>
<center><h1>403 Forbidden</h1></center>
<hr><center>Microsoft-Azure-Application-Gateway/v2</center>
</body>
</html>[15:01:34] [Server thread/ERROR]: Got an error with a html body connecting to https://api.minecraftservices.com/minecraft/profile/lookup/bulk/byname: <html>
<head><title>403 Forbidden</title></head>
<body>
<center><h1>403 Forbidden</h1></center>
<hr><center>Microsoft-Azure-Application-Gateway/v2</center>
</body>
</html>[15:01:35] [Server thread/ERROR]: Got an error with a html body connecting to https://api.minecraftservices.com/minecraft/profile/lookup/bulk/byname: <html>
<head><title>403 Forbidden</title></head>
<body>
<center><h1>403 Forbidden</h1></center>
<hr><center>Microsoft-Azure-Application-Gateway/v2</center>
</body>
</html>[15:01:35] [Server thread/INFO]: That player does not exist
I was able to replicate this too. running the newest version 1.21.4. No mods no plugin system pure vanilla and i get: