All, I was wondering if someone can help me. Below is my trigger which is very simple. It will take Feed item from Account page and will repost it to Chatter group. Trigger works fine for Post and Link, but when I`m trying to attach exisitng File from content library and share it, it generates below error.

Field_Integrity_Exception, ContentFileName is required field for feed post of type ContentPost. Content File Name: [ContentFileName]

Can someone pls suggest a workaround?

trigger autoPostFromAccToGroup on FeedItem (before insert) {

List <FeedItem> Feedlist = New List <FeedItem> ();

 Map <id,Account> AccMaps = New Map <id, Account> () ;
Set <Id> idsets = New Set <Id> ();

      For (Feeditem fe : Trigger.New) {
          String idStr = fe.Parentid;
           if(idStr.startsWith('001')){
                     idsets.add(idStr);    
           
      
      }
    }
    
       List <Account> accs = [SELECT ID, Owner.Name, RecordTypeid, Name FROM Account WHERE id IN :idsets ];
       
           for (Account  acc : accs) {
                   
            AccMaps.put(acc.id,acc);      

    
        
        
                   for (Feeditem f : Trigger.New) {
                   
                   if (AccMaps.get(f.parentid).Recordtypeid == '012300000000uth') {  
                   
            FeedItem FI = New FeedItem ();
            FI.ParentId = '0F91b0000008ThRCAU' ; 
            FI.TYPE = F.TYPE; 
            Fi.IsRichText = True;
            FI.Body = F.Body;
            Fi.LINKURL = F.LINKURL;
            Fi.TITLE = F.TITLE;
            Fi.ContentFileName = F.ContentFileName;
            Fi.ContentData = F.ContentData ;
            Fi.ContentDescription= F.ContentDescription;
           Fi.CreatedByid = UserInfo.getUserId() ;


            Feedlist.add(FI);

        
        }
        }
        }
         insert Feedlist;  
        
}