No "Slides" sidebar link "You do not have sufficient permissions to.." error

Just took over a WP site for a client. They are running this plugin 1.5.1v and have it working fine. I need to make some edits to the slides BUT there is no left side sidebar “Slides” option and when I go into PLugins page and try to click “settings” for this plugin I get an error “You do not have sufficient permissions to access this page.” as it tries to access the file xxxxx.com/wp-admin/edit.php?post_type=slide&page=slides_settings

Any ideas what is going on and why that sidebar Slides link is not there and why I get a permission issue when trying to access the settings?

https://www.ads-software.com/plugins/meteor-slides/