If you encounter an issue that you cannot change a user email address via Server API or the QuickBlox Admin Panel, please do the following:
1. Go to the QuickBlox Dashboard / Admin Panel.
2. Select your application.
3. Navigate to Users > Settings.
4. Uncheck "Require email confirmation (for application users)" in the User registration confirmation area.
After that, the issue should be resolved.
Feel free to check our official documentation for more information that will help you to integrate QuickBlox services into your applications / projects or contact our Support team by submitting a ticket if you have any other questions.