synchronization problem in sbi mobile banking

I have been using the Mobile banking regularly. But suddenly from 27.102015 I can’t use it. The application is logging in and asks for the options, but no options like balance enquiry, mobile topup, fund transfer etc works it simply replies to synchronize the application stating the code 904. I tried synchronize also by going to settings > synchronize > get key and entering it but it does not work. Kindly clarify what to do please.
Yours faithfully

Fakir Mohan Mahanta.
09439017136