too many authentications ????

hello,, i am using aldiko on android. and i bought books nearly for 2000 rupees. And i am android rom tester. each time after rebooting my android, aldiko asking for re authentication. and i am doing authentication each time i rebooted my device. and after some days it is saying too many authentications.i spend a lot of amount on books. and now i am not allowed to read MY BOOKS for which i PAID huge amounts.please help me .