@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/ZP4zRy8m48Pt_ueJdHawLMMe53iWLK... to http://www.plantuml.com/plantuml/png/~1ZP4zRy8m48Pt_ueJdHawLMMe53iWLK... 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: ZP4zRy8m48Pt_ueJdHawLMMe53iWLK9LLLHrFk8hM04xd9rI-kiR0u8a1CAG8SdpVja-DxP0nZNCCSiN x4ghbLivXeVnU2nJ9Vo9MABLMpOXa8N09OdQFq-Racn62RFR7WnIecAMx-Ig8Zl0B3YMZZNnFVZKV5UF fRfYteEs1oNFgKed7Oftv60oKw0DzpUgYrf9gTCBudxTnDdmXck2rtM1MUY7P-QFuF6f7-nRV3ZzLctS b7YDFPlUSQstgvwG_VG42_eL0kD7-FJ4eZXFWS74i0-WLkZz0D13RMVI96UKEQkxKTb4ftZDKmaHEy3m fP4qggxqot4UQveV3DJi8UflBQqSWMAAae-utuTE3zdma2qFTJDVrQKAXXVvKPawIq9NyUnshS7Du8lb nzh75ReowH-Gx7tYISRc%E2%80%94%E2%80%8BJEa_i7 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