CakePhp 3不唯一的表/别名：TableName

I've bin searching for days now without fixing this problem:

I am getting this error message:
Error: SQLSTATE[42000]: Syntax error or access violation: 1066 Not unique table/alias: 'Posts'

And this is my initialize method in the PostTable class:

public function initialize(array $config)
{
    parent::initialize($config);

    $this->table('posts');
    $this->displayField('post_id');
    $this->primaryKey('post_id');
    $this->addBehavior('timestamp');

    $this->belongsTo('Posts', [
        'foreignKey' => 'post_id',
        'joinType' => 'INNER'
    ]);

    $this->belongsTo('Users', [
        'className' => 'Users',
        'foreignKey' => 'fk_post_user_id', //<- foreignkey name are correct
        'joinType' => 'INNER'
    ]);

    $this->belongsTo('Pictures',[
        'foreignKey' => 'fk_post_picture_id',
        'joinType' => 'INNER'
    ]);
}

And this is my database:

i know the error has to do something with the foreignkeys of the posts table, but i don't know what is wrong with the belongTo in my initialize method.

Since you have self association you need to use a different alias for that association. So instead of

$this->belongsTo('Posts', [
    'foreignKey' => 'post_id',
    'joinType' => 'INNER'
]);

use

$this->belongsTo('ParentPosts', [
    'className' => 'Posts',
    'foreignKey' => 'post_id',
    'joinType' => 'INNER'
]);