how to fix: This class is not key value coding-compliant for the key 'key'?

Ok, so here is the thing, I am migrating from objective-c to swift. There's this class where the outlets(labels) are declared, this class is a UITableViewCell type. here is the code for reference:

class DetalleCodigoCell: UITableViewCell {
    @IBOutlet weak var CodigoNombre: UILabel!
    @IBOutlet weak var CodigoSitio: UILabel!
    @IBOutlet weak var CodigoCancelSitio: UILabel!
    @IBOutlet weak var CodigoInstancia: UILabel!
    @IBOutlet weak var CodigoCancelInstancia: UILabel!
           
    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }    
    override func awakeFromNib() {
        super.awakeFromNib()
    }    
    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)     
    } 
}

The table is created at the main ViewController, so I reference the labels that show the data there, just like this:

class CodigosRutasViewController: UITableViewController, DZNEmptyDataSetDelegate, DZNEmptyDataSetSource, UIAdaptivePresentationControllerDelegate {

 override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let codeCell: DetalleCodigoCell = tableView.dequeueReusableCell(withIdentifier: "CodigoCell", for: indexPath) as! DetalleCodigoCell
        codeCell.CodigoNombre.adjustsFontSizeToFitWidth = true
        codeCell.CodigoNombre.text = codes![indexPath.row] as? String
        codeCell.CodigoSitio.text = codes![indexPath.row] as? String
        codeCell.CodigoCancelSitio.text = codes![indexPath.row] as? String
        codeCell.CodigoInstancia.text = codes![indexPath.row] as? String
        codeCell.CodigoCancelInstancia.text = codes![indexPath.row] as? String
        return codeCell   
    }
}

when it comes to show the data the application crashes and the following error is shown. Error: *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UITableViewCell 0x7fe3a042f1a0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key CodigoCancelInstancia.'

I do have my outlets referenced correctly inside the storyboard view, which is wierd because I don't know any other reason for this error to appear. Any idea?