Post.cs | Stack Overflow | How to resolve ModelState.IsValid = false while binding a List type?

gistfile1.txt

public class Post : IEntity
{
    [Key]
    public int Id { get; set; }
    [Required]
    public string Title { get; set; }

    public string URL { get; set; }

    [Required]
    public string IntroText { get; set; }
        
    [Required]
    public string Body { get; set; }

    [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
    [Column(TypeName = "DateTime")]
    public DateTime Created { get; set; }

    [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
    [Column(TypeName = "DateTime")]
    public DateTime? Modified { get; set; }
    [Required]
    public string Author { get; set; }
    public List<Comment> Comments { get; set; }

    public List<Tag> Tags { get; set; }

}