Django says that model has no ForeignKey to another model but it really does

Question

Will you help me to figure out why Django raises this error?

SolutionsForLanguagesApp.LanguageLevel: (fields.E336) The model is used as an in termediate model by 'SolutionsForLanguagesApp.UserProfile.languages', but it does not have a foreign key to 'UserProfile' or 'Language'.

I'm confused because, as you can see, there is a foreign key to Language in LanguageLevel already:

class LanguageLevel(models.Model):
    language = models.ForeignKey(Language)
    level = models.ForeignKey(Level)

    class Meta:
        unique_together = (('level', 'language'),)

Do you know what to do?

EDIT - Added UserProfile:

class UserProfile(models.Model):
    user = models.OneToOneField(User, related_name='userprofile')
    date_of_birth = models.DateField(null=True, blank=True)
    telephone = models.CharField(max_length=40, null=True, blank=True)
    IBAN = models.CharField(max_length=40, null=True, blank=True)
    created = models.DateTimeField(auto_now_add=True)
    modified = models.DateTimeField(auto_now=True)

    MARITAL_STATUS_CHOICES = (
        ('single', 'Single'),
        ('married', 'Married'),
        ('separated', 'Separated'),
        ('divorced', 'Divorced'),
        ('widowed', 'Widowed'),
    )
    marital_status = models.CharField(max_length=40, choices=MARITAL_STATUS_CHOICES, null=True, blank=True)

    HOW_DO_YOU_KNOW_ABOUT_US_CHOICES = (
        ('coincidence', u'It was coincidence'),
        ('relative_or_friends', 'From my relatives or friends'),
    )
    how_do_you_know_about_us = models.CharField(max_length=40, choices=HOW_DO_YOU_KNOW_ABOUT_US_CHOICES, null=True,
                                                blank=True)

    # TRANSLATOR ATTRIBUTES

    is_translator = models.BooleanField(default=False)

    # language_tuples = models.ManyToManyField(LanguageTuple,blank=True)
    languages = models.ManyToManyField(Language, through='LanguageLevel')

    rating = models.IntegerField(default=0)

    number_of_ratings = models.BigIntegerField(default=0)

    def __unicode__(self):
        return '{} {}'.format(self.user.first_name, self.user.last_name)

    def __str__(self):
        return '{} {}'.format(self.user.first_name, self.user.last_name)

Answer 1

Your LanguageLevel model is missing a ForeignKey to the UserProfile:

class LanguageLevel(models.Model):
    language = models.ForeignKey(Language)
    level = models.ForeignKey(Level)
    # Add Foreign Key to UserProfile
    userprofile = models.ForeignKey(UserProfile)

    class Meta:
        unique_together = (('level', 'language'),)

Also I'm not sure that the unique_together constraint is what you want - it will mean that only one user can have any one combination of language/level. A more likely constraint would be ('userprofile', 'language') so that a language can only be mapped to a user once.