@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/06tq404I5ENsC6cXKT6xxgxaBDG3o_... to http://www.plantuml.com/plantuml/png/~106tq404I5ENsC6cXKT6xxgxaBDG3o_... 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: 06tq404I5ENsC6cXKT6xxgxaBDG3o_tzkTRbkDJuRa4mYLIoIEFVZsapwhAr5NDHB0jrZfWK5MOp8y53 KKy_J2adzUr-HCAJ8bVfEA7x6qMwXhNtcUJYCT4gMZV_c2gzJk9gimqo81bOfXLN-tkYpiaWi3aabF_w rItuxPLX5NINL6FKhAboWjmXbI8jiBfIRnXs0h40re09D-HpekC83iDO8GEXFHTCMoPlXmKCx05mLK_f TdsZCJY1geDzQhs6aar6qIIfU1V5QYHQ5wvIFj8v6xZE0zWeZksK6S5mgnjDR9L1ao9uZg7-gFLepB1E eGVeUILgETgbkEtuAelaPmmGV7kEDjEioz1d6D_0WvvYzGbScBwP8CnA9ZosEQ2vGlBk_7W00 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       PNG  SVG  ASCII Art