I solved the issue from below site.
https://community.arubanetworks.com/t5/Controller-Based-WLANs/Configuration-changes-in-Managed-Device/ta-p/393395
I will share procedures for anyone who have same issue.
During password recovery, those two are important.
1) #local-config enable
2) Don't forget write terminal before exit. Some password recovery sample doesn't write terminal so that it cuases failure.
User: password
Password:forgetme!
(Aruba7005) #configure terminal
This controller is managed by a Mobility Master.
Configuration changes can only be performed on the Mobility Master.
(Aruba7005) #local-config enable
Warning: 'local-configure enable' should only be used for debugging. This will disableAuto-Rollback feature. Please use the command 'local-configure disable' after you are done.
Configuration Mode Is Enabled.
(Aruba7005) ^#configure terminal
Enter Configuration commands, one per line. End with CNTL/Z
(Aruba7005) ^(config) #mgmt-user admin root
Password:********
Re-Type Password:********
(Aruba7005) ^(config) #write memory
Saving Configuration...
Configuration Saved.
(Aruba7005) (config) #exit
(Aruba7005) #exit
User: admin
Password: