<PackageReference Include="Relativity.Server.Services.Interfaces.SDK" Version="5000.0.2" />

Relativity.Services.Objects.DataContracts.TextFieldError

public class TextFieldError
Represents a value for a text field that could not be properly returned.
public string ErrorMessage { get; set; }

The error message describing why the field value could not be returned.

public TextFieldError()