How to join 4 tables in linq ef core

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LINQ

ASP.NET-Core

I'm implementing an asp.net core project. I wrote a linq query like below, however it returns null:
If I omit the last two join, my query works correctly and it returns 1000 elements.My problem is how to join these 4 tables in order to work correctly. I appreciate if anyone helps me.

What I have tried:

var apiapp = (from a in _context.Apiapp
join b in _context.Api on a.Apiid equals b.Id

join c in _context.App on a.AppId equals c.Id

join d in _context.Item on a.ItemId equals d.Id
where a.IsDeleted.Equals(false)
select new { ID = a.Id, Status = a.Status, mDate = a.mDate, name=c.name, item=d.item}).ToList();