Board manager error

[Anik96 1]

I cant compile codes for tm4c123g anymore. My boards suddenly disappeared from board manager. Now when I want to open it, it shows the following error:

 

Error downloading http://www.energia.nu/packages/package_index.json
java.lang.RuntimeException: java.lang.Exception: Error downloading http://www.energia.nu/packages/package_index.json
    at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onUpdatePressed$0(ContributionManagerUI.java:151)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.Exception: Error downloading http://www.energia.nu/packages/package_index.json
    at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:113)
    at cc.arduino.contributions.packages.ContributionInstaller.download(ContributionInstaller.java:330)
    at cc.arduino.contributions.packages.ContributionInstaller.downloadIndexAndSignature(ContributionInstaller.java:305)
    at cc.arduino.contributions.packages.ContributionInstaller.updateIndex(ContributionInstaller.java:283)
    at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onUpdatePressed$0(ContributionManagerUI.java:147)
    ... 1 more
Caused by: java.io.IOException: Received invalid http status code from server: 416
    at cc.arduino.utils.network.FileDownloader.downloadFile(FileDownloader.java:194)
    at cc.arduino.utils.network.FileDownloader.download(FileDownloader.java:128)
    at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:111)
    ... 5 more