Make a column is required for a document library

I follow the following step to set up the column is required. However, it works for one serve (it does not let me save document if the column is empty) but not for another server (it let me save document without data in the column). I do not know if any server setting make the difference?  I will appreciate your help.

1. Go to Document Library Settings
2. Click on Advanced Settings
3. Select 'Yes' for the option 'Do you want to manage the content types ?' and Save
4. Click on 'Document' link under Content Types section
5. You will see all the column listed
6. Click on 'Title' and now you can make it required field.
7. Save the changes