@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/bLHHRzem47xFhxX5bKYa0ghKfqr8fO... to http://www.plantuml.com/plantuml/png/~1bLHHRzem47xFhxX5bKYa0ghKfqr8fO... 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: bLHHRzem47xFhxX5bKYa0ghKfqr8fO3QXm8Lj9hwX9puIAmcTcGxfMZQVvyF4vg6RTgUsllkxlEN--wu CPPfMvT5y4N8jAWvGcvjPRuEXvhj1fcmUPtK1dMgf4Lf1wagXrN19FNqZUM5I8QJw_uZGS_pXs79Z4Nj eCr4bPMIr5CHVz23vuepYs1pX0mbQf52ech9cTw3iVi2WKb-I8TcxsZAy192Hu2wqi8WHII32TSRDgq2 ZMysO9KA_1ktHzer9QAB99keGkbHcAc2EvgBhQCvGebMEqbOeZH7_GcDdU 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