Your ROOT_URL in app.ini is http://git.osmesh.ru/ but you are visiting https://git.osmesh.ru/MOS/OpenBoard/blame/commit/89709f47dc26505b074fe62b0405d33ebd10414e/resources/etc/SankoreEditor/editor_en/index.html
You should set ROOT_URL correctly, otherwise the web may not work correctly.
<td><p>Sankoré Editor allows you to create rich interactivity scenarios. Create interactive content easily with basic activities that can be used in various subjects (attach images, sounds, order of words, phrases, create categories ...). This content can then be added to the software Open-Sankore. </p></td>
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<td><p>Requirement to work with the editor :</p>
<ul>
<li>a Web access</li>
<li>an account on Planète Sankoré</li>
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<td><divalign="center">
<p> </p>
<p><ahref="http://editeur.sankore.org"title="Editeur"target="_self"class="c">Click here to connect to the Sankoré Editor</a></p>
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<td><p> </p>
<p> </p>
<p> </p></td>
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<td>Sankoré editor is hosted on <ahref="http://planete.sankore.org/"target="_self">planete.sankore.org</a></td>