Are you working on Lightroom 6 or CC, as Dehaze is a part of Lightroom CC.
Please make sure you have the latest version of on1 in order to have it compatible with new Lightroom.
Please check the below link for more information
What about the plug ins that allow me to move back and forth between lightroom and ON1? I can move from ON1 to lightroom very easily but not back to ON1.
Please update your Perfect suite version to 9.5 from the below link and then run its installer.
And once you run the installer it will automatically detect Lightroom application and will install its plugin in it , so that you can access it from Lightroom.
Please let us know if it works.