This might be discussed before. But, I cannot find the solution for my specific trouble.
I was trying to run a shiny app on EC2, but failed to render plots due to the failure to start a PNG device obviously. My R version is 3.5.1, Ubuntu version is 16.04. The error msg is like:
Warning in pngfun(filename = filename, width = width, height = height, res = res, :
unable to open connection to X11 display ''
Warning: Error in .External2: unable to start device PNG
123: pngfun
122: startPNG
121: drawPlot
107: <reactive:plotObj>
91: drawReactive
78: origRenderFunc
77: output$umi_cell_ranking
1: runApp
capabilities() result is as below:
jpeg png tiff tcltk X11 aqua
TRUE TRUE FALSE FALSE TRUE FALSE
http/ftp sockets libxml fifo cledit iconv
TRUE TRUE TRUE TRUE TRUE TRUE
NLS profmem cairo ICU long.double libcurl
TRUE FALSE FALSE TRUE TRUE TRUE
I assume I installed necessary libraries as guided by online trouble shooting, but not sure complete. Anybody met this before and got a solution?