I'm using sitecore 9.1.1

I'm trying to get contact who's first name is "myfirstnametest" but I'm getting count zero in result for contacts even I have record with this contact facet.

```
using (Sitecore.XConnect.Client.XConnectClient client = Sitecore.XConnect.Client.Configuration.SitecoreXConnectClientConfiguration.GetClient())
            {
var results3 = client.Contacts.Where(c => c.GetFacet<PersonalInformation>().FirstName == "myfirstnametest").GetBatchEnumerator();
}

```