Nerdaryan,
This error appears to be common, as it arose with: sagar.atalatti, KTS915, sundev, steve53990, and now me. Anspress has completely broken my WordPress install, and I now cannot access my wp-admin login page, or the admin sections of my site as a whole.
Please post a fix here for this issue.
Your prior thread (https://wordpress.org/support/topic/you-do-not-have-sufficient-permissions-to-access-this-page-209?replies=12) indicates that it has been resolved. Please share the resolution with us and please implement it into the code of Anspress.
It's really not fair that we should download your plugin, only to break our installations. Even a free plugin should refrain from that. It's even less fair that you have not shared your resolution for this completely destructive bug.