I have started getting an error when login as admin. I haven't installed any new modules or made changes to the website. It happens on the site you're redirected to when logging in.

The error is

Odoo Server Error
Traceback (most recent call last):
  File "/opt/odoo/odoo10/odoo/http.py", line 638, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/opt/odoo/odoo10/odoo/http.py", line 675, in dispatch
    result = self._call_function(**self.params)
  File "/opt/odoo/odoo10/odoo/http.py", line 331, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/opt/odoo/odoo10/odoo/service/model.py", line 119, in wrapper
    return f(dbname, *args, **kwargs)
  File "/opt/odoo/odoo10/odoo/http.py", line 324, in checked_call
    result = self.endpoint(*a, **kw)
  File "/opt/odoo/odoo10/odoo/http.py", line 933, in __call__
    return self.method(*args, **kw)
  File "/opt/odoo/odoo10/odoo/http.py", line 504, in response_wrap
    response = f(*args, **kw)
  File "/opt/odoo/odoo10/addons/web/controllers/main.py", line 885, in call_kw
    return self._call_kw(model, method, args, kwargs)
  File "/opt/odoo/odoo10/addons/web/controllers/main.py", line 877, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/opt/odoo/odoo10/odoo/api.py", line 681, in call_kw
    return call_kw_multi(method, model, args, kwargs)
  File "/opt/odoo/odoo10/odoo/api.py", line 670, in call_kw_multi
    recs = self.with_context(context or {}).browse(ids)
  File "/opt/odoo/odoo10/odoo/models.py", line 4881, in with_context
    context = dict(args[0] if args else self._context, **kwargs)
ValueError: dictionary update sequence element #0 has length 9; 2 is required

I can still use the site. The problem is that I have no clue what is causing it. Has anyone an idea how to figure out what is the problem or how to figure out what the problem is? It's a live site on a production odoo server, so my options of debugign are limited.