Could not connect to the Processing server to install libraries

May I know how to solve this issue? I am using Processing 3.5.4.

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I’m also getting it! :scream:
It attempts this URL: :globe_with_meridians:
But it gets this HTTP response code error 500: :ghost:


Getting the same error here.

It is most unlikely that there is a user work-around and that the issue can only be solved by the Processing team. They may well decide that amount of work needed to fix it is not worth it for an older version of Processing.

Unless you have a specific need for 3.5.4 I suggest you use the latest version 4.3

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I reported the same issue in another thread a couple of weeks ago. I really wish this issue would be solved, as I would like to use Processing 3 Python mode in my computer science classes.

Processing 4 does have a Python mode but it is difficult to use, as error checking is virtually non-existent. My hope is that the Processing team can either make Processing 3 Python mode available again, or find someone to work on Processing 4 Python mode, to make it more usable.

Try this


  • If you are under some restrictive proxy our without Internet acess you can download and manualy copy it (on Windows & Mac OS) under Documentos > Processing > modes > PythonMode. On Linux, under your sketchbook folder/material-aulas.

You can download your library as zip file manually and extract it to processing libraries folder

The links to the libraries are available here: Thanks @GoToLoop for providing this!
I would save a copy of this somewhere in case it is not available in the future for any reason!

Adding a Processing library:
Adding a Processing Li... | Wiki | UAL Creative Computing Institute

Some code I wrote to save a file with links or name of zip file (modify for this):

String [] contrib;
int count = 0;

void setup()
  contrib = loadStrings("");
  for(int i=0; i< contrib.length; i++)
    if (contrib[i].contains("download="))
      //int lastIndex = contrib[i].lastIndexOf("/");
      //String ss = contrib[i].substring(lastIndex+1);
  println("Count: ", count);
  String links [] = new String [count]; 
  int ix=0; 
  for(int i=0; i< contrib.length; i++)
    if (contrib[i].contains("download="))
      links[ix++] = contrib[i].substring(9);
  saveStrings("links.txt", links);   

You can certainly download them one at a time.

I used wget to archive all the zip files locally:

I had some fun downloading them all in Processing and also with command-line scripts.
I will leave this adventure for the enthusiastic!


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Hello everyone,

A fix for the ‘Could not connect to the Processing server’ error in Processing 3 has been implemented and deployed. You should now be able to view and download libraries, tools, and modes from both Processing 3 and 4.

We are currently monitoring the results to ensure the issue is fully resolved. Thanks to everyone who reported this problem. Your input has been invaluable in addressing this issue.

Please continue to share any feedback or bugs you encounter.

The Processing Foundation Team

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