'Shibboleth (Request missing SAMLRequest or SAMLResponse form parameter)

Good morning people! I'm trying to make a POST request on shibolleth with the following code:

import requests as requests
link = 'https://[IP]/Shibboleth.sso/SAML2/POST'
requisicao = requests.Session().post(url=link,verify=False)
print(requisicao)
print(requisicao.text)

However, an HTML is returned with the following information:

<Response [500]>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html 
    PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 
    "DTD/xhtml1-strict.dtd">
    
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <link rel="stylesheet" type="text/css" href="/shibboleth-sp/main.css" />
    <title>opensaml&#58;&#58;BindingException</title>
</head>

<body>


<h1>opensaml&#58;&#58;BindingException</h1>

<p>The system encountered an error at Mon May 23 11&#58;48&#58;22 2022</p>

<p>To report this problem, please contact the site administrator at
<a href="mailto:root@localhost">root@localhost</a>.
</p>

<p>Please include the following message in any email:</p>
<p class="error">opensaml&#58;&#58;BindingException at (https&#58;//shibboleth.unifeob.edu.br/Shibboleth.sso/SAML2/POST)</p>

<p>Request missing SAMLRequest or SAMLResponse form parameter.</p>



</body>
</html>

Does anyone know which parameter is missing? Could it be SSL?



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