Unable to select depart date in https://spicejet.com through Selenium and Java

I am trying to select a "Depart date" as of 31st october 2018 from the calender https://spicejet.com/ But I am getting error "unknown error: Element is not clickable at point (832, 242). Other element would receive the click: ..." Please help me out. Here is my code getting such exception:

public class bookflight extends Thread {

    UtilityMethods utilObj= new UtilityMethods();
    @Test
    public void SighnUp() throws IOException
    {
        utilObj.getdriver().get("https://spicejet.com");
        utilObj.getdriver().manage().window().maximize();

        utilObj.getdriver().findElement(By.id("ctl00_mainContent_ddl_originStation1_CTXT")).click();
        utilObj.getdriver().findElement(By.xpath("//a[contains(text(),'Guwahati (GAU)')]")).click();
        utilObj.getdriver().findElement(By.xpath("//a[contains(text(),'Goa (GOI)')]")).click();
        utilObj.getdriver().findElement(By.className("ui-datepicker-trigger")).click();
        utilObj.getdriver().findElement(By.xpath("//div[@class='ui-datepicker-group ui-datepicker-group-first'])/parent:://table[@class='ui-datepicker-calendar']following-sibling::./a/contains(text(),'31')")).click();           
    }
}