@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/image/bPBFJiGW4CRlJVeEd4tw0iQO... to http://www.plantuml.com/plantuml/png/~1image/bPBFJiGW4CRlJVeEd4tw0iQO... 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: image/bPBFJiGW4CRlJVeEd4tw0iQOrDR3NapZwWEmC2e9XNKO3YG-lFIFRhiBrRsHRtxVnp33XvB0X4 AXeIpAWXyS8HV4wldm39yU7Bs4urXFoEpkgwfOQrk58AZZeGTpRijNsKtMt09nfTsKiP5GLVTibcj1of h6IhZ6TSr53O9Kr72KArTPN6QD_0DtIjIzDLF4BVCEid0j9O9pVv33nDRoZg3_H_mUj0PSgZD_xlZDkt p19lfuu64GqiYcjKChlOY39NYt67wccXptUX5ZMnEVf-FDW3lpPXVhEWbJytrqB3QGObvT5DfSDIeTrm Ep9qxUdVvXWWLqrZpnFat4zrbl2CDMngBPRm00 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