The WP Toolbar (also known as the admin bar) is a core feature of WordPress user settings. The Simple Membership Plugin does not modify it unless specific settings within the plugin are enabled.
Please check the following settings in the plugin:
Settings → Advanced Settings → WP Toolbar and Admin Dashboard Related
Ensure that none of the toolbar-related options are enabled in this section. These settings are disabled by default, so if they are affecting the toolbar visibility, it’s likely that they were manually enabled at some point.