Someone probably already answered this, but I had the same problem. I couldn’t get the cartpauj PM application to send messages to my emr portal, but Devnia did work. unfortunately, my icons were looking for the “cartpauj” directory, not the “devnia-pm-based-on-cartpauj-pm”, directory they were in. So, I simply created a cartpauj-pm directory on my server, in the plugin directory. I then copied the images folder to the directory, and walla…the icons showed up. I’m not sure why the directory is devnia-pm-based-on-cartpauj-pm, when it is cartpauj-pm.
Bootstrap Devnia PM based on Cartpauj-PM