WSO2 : can't login superadmin after password change - authentication

Question

After changed password of user "admin", i can't login to device manager.
Welcome screen it turning and then tell me that there is an error :
[2017-10-23 10:11:41,401] [IoT-Core] ERROR {org.wso2.carbon.apimgt.impl.AMDefaultKeyManagerImpl} - Invalid OAuth Token : Invalid access token
[2017-10-23 10:11:41,401] [IoT-Core] ERROR {org.wso2.carbon.apimgt.rest.api.util.impl.WebAppAuthenticatorImpl} - Authentication failed. Please check your username/password
[2017-10-23 10:11:41,401] [IoT-Core] WARN {org.apache.cxf.phase.PhaseInterceptorChain} - Interceptor for {http://store.api.rest.apimgt.carbon.wso2.org/}SwaggerJsonApi has thrown exception, unwinding now
org.apache.cxf.interceptor.security.AuthenticationException: Unauthenticated request
It seems to have a fix (https://github.com/wso2/product-iots/issues/1033) but how can i fix it in 3.1.0?
Edit : I've changed db from H2 to mysql and now i can't change admin password in device management console.
i cant add user anymore too.
error in user management :
DataTables warning: table id=user-grid - Ajax error. For more information about this error, please see http://datatables.net/tn/7
error when i try to change admin password showed in browser:
900908Resource
forbidden Access failure for API:
/api/device-mgt/v1.0/users/1.0.0, version: 1.0.0 status: (900908) -
Resource forbidden
Backed to H2 DB for this part, still no luck. When admin password changed, device manager in not accessible for super admin.
Edit2 :
I've found a trick.
Backed to H2 for user management, i've created another user with all roles.
Then i've changed admin password to "disable" it.
It works, my new admin have all roles.
But when admin password is changed, access to store is forbidden.
this article says it fixed : https://wso2.org/jira/browse/EMM-1295
I've rechanged admin pass, no message. Maybe i made a mistake.
Thanks.
Regards,
Alex.

Answer 1

After searches, i found this :
https://docs.wso2.com/display/IoTS310/Changing+the+Super+Administrator+Username+and+Password
Tested and OK.
YOu have to change password on the webinterface carbon.
And follow the instruction on link above.