Fields except Id and Tile are NULL

I'm facing a problem, all fields except ID, Title, Created, etc.. are Null, so all custom columns won't load any value.

I Tried to load the ListItems with Include, but result is still the same.

What am I doing wrong?

var participants = Spo.GetParticipants(true);

var oList = Ctx.Web.Lists.GetByTitle("Participant");
var camlQuery = new CamlQuery
{
    ViewXml = "<ViewScope='RecursiveAll'><RowLimit>5000</RowLimit></View>"
};
var listItems = oList.GetItems(camlQuery);
//Ctx.Load(listItems,
//    items => items.Include(
//        item => item["ID"],
//        item => item["Title"],
//        item => item["Email"],
//        item => item["FirstName"],
//        item => item["Company"],
//        item => item["Phone"],
//        item => item["Street"],
//        item => item["ZipCode"],
//        item => item["City"]), items => items.ListItemCollectionPosition);
Ctx.Load(oList);
Ctx.Load(listItems);
Ctx.ExecuteQuery();

foreach (var oListItem in listItems)
{
    foreach (var it in participants)
    {
        if (oListItem != null && oListItem["Email"].ToString() == it.Email)
        {
            oListItem["FirstName"] = it.FirstName;
            oListItem["LastName"] = it.LastName;
            oListItem["Company"] = it.Company;
            oListItem["Phone"] = it.Phone;
            oListItem["Street"] = it.Street;
            oListItem["ZipCode"] = it.ZipCode;
            oListItem["City"] = GetLookupCity(it.City);
            //FieldLookupValue lv = new FieldLookupValue();
            //lv.LookupId = int.Parse() it.City
            p = "UPDATED: " + it.Email;

        }
        else
        {

        }

    }
}

There should be something wrong with camlquery. There should be blank between View and Scope

<View Scope='RecursiveAll'><RowLimit>5000</RowLimit></View>