@startuml legend The plugin you are using seems to generated a bad URL. This URL does not look like DEFLATE data. It looks like your plugin is using HUFFMAN encoding. This means you have now to add an header ~1 to your data. For example, you have to change: http://www.plantuml.com/plantuml/png/LLB1ReCm3BtdAwoUEgdT1_HGgM8N3f... to http://www.plantuml.com/plantuml/png/~1LLB1ReCm3BtdAwoUEgdT1_HGgM8N3f... It will work this way You may contact the PlantUML team at plantuml@gmail.com But you should also probably contact the plugin authors you are currently using and send them this image For the record, here is your data: LLB1ReCm3BtdAwoUEgdT1_HGgM8N3fKYGBrKEsJWqcoGC2UKmxH_dnD2st59_Fnil-UmVe5LWJVjj3Lk 1Sf1SHAxDxnXPmUa7Mpt0J7M8tnOxsqFzW9F107yLLU4EmIJxZf0Kzi6eVJAD8eQ1tn2WT-Z9kpHU1Tc JTXriK6ua_RQjA3xeOiCvLaJX2wl0hauQ13dmyWQa5gazr1rE8frj31OfxqbZSc5d3MJRgy- endlegend @enduml Submit amiga aws-orange black-knight bluegray blueprint cerulean-outline cerulean crt-amber crt-green cyborg-outline cyborg hacker lightgray mars materia-outline materia metal mimeograph minty plain reddress-darkblue reddress-darkgreen reddress-darkorange reddress-darkred reddress-lightblue reddress-lightgreen reddress-lightorange reddress-lightred sandstone silver sketchy-outline sketchy spacelab spacelab-white superhero-outline superhero toy united vibrant       🎉 Discover the future PlantUML Web Editor! 🚀  PNG  SVG  ASCII Art