Pulling Custom Attributes by and by object

I am having an issue where when I try to pull a custom attribute from my DTO objects via an object compared to T it is coming back null. When I do it by generic type, it works.  I am having to do this because I need to cycle all the DTO properties to get all the properties that have a specific attribute. Can someone find out what I am doing wrong?  Also I wrote some custom code to pull all the objects that need to be checked and I was curious if there is a quick way to do this?
PropertyDTO:
    public class PropertyInformationDTO     {         public string DTOPropertyNm { get; set; }         public string DTOPropertyType { get; set< ...