matrix-org_synapse/synapse/res/templates/sso_auth_bad_user.html

{% extends "_base.html" %}
{% block title %}Authentication failed{% endblock %}

{% block header %}
<style type="text/css">
    {% include "sso.css" without context %}
</style>
{% endblock %}

{% block body %}
<div class="error_page">
    <header>
        <h1>That doesn't look right</h1>
        <p>
            <strong>We were unable to validate your {{ server_name }} account</strong>
            via single&nbsp;sign&#8209;on&nbsp;(SSO), because the SSO Identity
            Provider returned different details than when you logged in.
        </p>
        <p>
            Try the operation again, and ensure that you use the same details on
            the Identity Provider as when you log into your account.
        </p>
    </header>
</div>
{% include "sso_footer.html" without context %}
{% endblock %}