@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/TP91Rnen48Nl_XMlFhK7gZPKFQ0g2W... to http://www.plantuml.com/plantuml/png/~1TP91Rnen48Nl_XMlFhK7gZPKFQ0g2W... 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: TP91Rnen48Nl_XMlFhK7gZPKFQ0g2WcYH2gHoXBbY8Rr01QxDh5dsvAA_zx5OjcbIcxhUM_jxytCJHGA KfM5UYSRBXab2GTBFLz9OHqh5RVMxIXGYINbstNmbJDtll01lpTMkACRNb5LoDWxUQ2ICQwa2lIw8RCl ZCzVLS4hWNW4kzu8Z0sSY_LEAUSDGpzbLv_wLtXYgka2Cg6ZgXNbuaCjynAFaODMof3GaY93PtjNuwtt U1Xc6dyLi0f7d97FjnnI0Q0rEy7tG2job2hd2-xTggZ-Z6vLAfyiwFMkpme6E7ueuA0E3Ufi_gENZMQw EKzyoHZ6QAEGamI2dGzY7HwpspELFc6zdmmnDARdNVoWJv0v1GCTf5XywVTnvvsGTHnYexT1Jfx_gdfO YSV8njp_uh3NeDWu5sII-N2PVUhZSsL5V0hVCUDRtO1MnW3biqZNX5Vrz43kovrtYUYoAtMcm1Tfxvtm EgGfnrHluxJjfuWDBMmwckMbQVfpFZyPpeI7nA7GuQlJD9Q 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