Hi, Hive account@zhanmusi. We have notice that you have been delegating to us several times today. To correctly delegate SP to us, you must increase the Steem Power (SP) in total. For instance, if you have delegated 1000 SP to us and you want to delegate 500 more, you need to put down 1500 in the SP amount to delegate box. Do not just put down 500, or 500 will be subtracted and will become unavailable for you during the next 7 days. You can use our delegation tool and read more about it at our website: https://www.brupvoter.com/en/delegation.html. Best regards, Hive account@brupvoter TEAM.