If you wish to use Optin Monster plugin with the OptimizePress Suite of tools, you should read this article to ensure that everything works correctly.
To run Optin Monster, you just need to make a few tweaks:
1. Turn on CSS and JS for OptinMonster on Scripts And Styles settings (you will find this inside OptimizePress > Settings > Styles & Scripts and then check the boxes next to Optin Monster to ensure their scripts can run on OP3 pages. See our guide on activating styles and scripts here.
2. Set your campaign to be visible on pages