I have an API end point that takes a query string parameter but the value returned is always null even when a value is passed.

This is my method in Blazor web app,

   public async Employee GetEmployee(EmployeeDetails details)
    {
        var qString = string.Empty;
    
        if (details != null)
        {
            if(details.EmployeeId != null)
            {
                qString += "empId=" + details.EmployeeId;
    
                var employee = await _httpClient.GetAsync($"api/EmployeeData/GetData?{qString}");
    
                return employee;
            }
    
        }

}

I have the following endpoint in the employee data controller within the api,

public async Task<ActionResult<Employee>> GetData([FromQuery] string? Id)
{
    ///The value of query string Id is always null here.
}

Am I missing something? Could someone point me in the correct direction please?

Thanks in Advance