Hi, Alex.
Did you configure the "email" scope as a default scope in admin web UI? Unless you did, dynamically registered clients won't be able to request it without you first adding the scope to them in web UI. It's a security measure, as some scopes may be too sensitive to release them to just any client which decided to register at this OP.
>Question 2: how to create client and register with WordPress ?
You can easily create a client manually at your Gluu instance and assign any scope you wish to it there. Please check [this page](https://gluu.org/docs/ce/3.0.1/admin-guide/openid-connect/#client-registration-configuration) for details.