how install the udooneo board at arduino ide on MacBook? I get error message

Error downloading http://downloads.arduino.cc/packages/package_index.json
java.lang.RuntimeException: java.lang.Exception: Error downloading http://downloads.arduino.cc/packages/package_index.json
at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onUpdatePressed$0(ContributionManagerUI.java:151)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.Exception: Error downloading http://downloads.arduino.cc/packages/package_index.json
at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:131)
at cc.arduino.contributions.packages.ContributionInstaller.download(ContributionInstaller.java:334)
at cc.arduino.contributions.packages.ContributionInstaller.downloadIndexAndSignature(ContributionInstaller.java:309)
at cc.arduino.contributions.packages.ContributionInstaller.updateIndex(ContributionInstaller.java:287)
at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onUpdatePressed$0(ContributionManagerUI.java:147)
... 1 more
Caused by: java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:592)
at java.lang.Integer.valueOf(Integer.java:766)
at cc.arduino.net.CustomProxySelector.manualProxy(CustomProxySelector.java:146)
at cc.arduino.net.CustomProxySelector.getProxyFor(CustomProxySelector.java:71)
at cc.arduino.utils.network.FileDownloader.downloadFile(FileDownloader.java:153)
at cc.arduino.utils.network.FileDownloader.download(FileDownloader.java:128)
at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:129)
... 5 more

 

This errors do not seem to be Udoo related. Perhaps a search on the Arduino forum will help you?