django - Date filter: wrong format -

I have this field in the post model:

  created = model.datafilefield (_ ('Created'), default = datetime.now)  

I have this in my template:

  {{post.created | Date: "SHORT_DATE_FORMAT"}}  

I have my settings / I have:

  LANGUAGE_CODE = 'this' USE_L10N = True  < / Pre> 
 But I get this: 
 
 th03-0500RCDT_marAMCDTE_maggio-0500RmagamCDT 
 
 Why? 
 
 This is the document: