Currently, all versions of China Eastern Airlines 东方航空 websites (e.g. http://sg.ceair.com/, hk.ceair, etc) are not working.
I tried searching for a ticket in December and an error message popped out: We apologize that there are insufficient seats on ## segment of your searched flight. Please change the search options. Thank you for your cooperation!
I called the customer service and they confirmed that it is an error (their system shows that there are indeed still plenty of seats). Hope they fix it soon.