Error: 500 Internal Server Error

Sorry, the requested URL 'https://qdev.perspectivia.net/en/portal/start' caused an error:

Internal Server Error

Exception:

ParseError('mismatched tag: line 18, column 2',)

Traceback:

Traceback (most recent call last):
  File "/var/storage/host/qp/current/python/bottle.py", line 862, in _handle
    return route.call(**args)
  File "/var/storage/host/qp/current/python/bottle.py", line 1740, in wrapper
    rv = callback(*a, **ka)
  File "/var/storage/host/qp/current/python/mws_quellen/web_io.py", line 193, in return_page
    'text': text,
  File "/var/storage/host/qp/current/python/bottle.py", line 3619, in template
    return TEMPLATES[tplid].render(kwargs)
  File "/var/storage/host/qp/current/python/bottle.py", line 3409, in render
    self.execute(stdout, env)
  File "/var/storage/host/qp/current/python/bottle.py", line 3396, in execute
    eval(self.co, env)
  File "/var/storage/host/qp/current/python/mws_quellen/views/start_main.tpl", line 13, in <module>
    % article = dao.ET.fromstring(text.decode()).find('article')
  File "/usr/lib/python3.5/xml/etree/ElementTree.py", line 1344, in XML
    parser.feed(text)
  File "<string>", line None
xml.etree.ElementTree.ParseError: mismatched tag: line 18, column 2