Have you assigned the relevant Email Connector module roles to your Administrator role in the application's Security?
https://docs.mendix.com/appstore/connectors/email-connector/#21-module-security-and-roles
https://docs.mendix.com/refguide/user-roles/
You'll also need to have the ACT_EmailAccount_LaunchEmailConnectorOverview microflow linked to a page to access the Email Connector admin pages.
https://docs.mendix.com/appstore/connectors/email-connector/#setup
I hope this helps, good luck!