Error downloading https://downloads.arduino.cc/libraries/library_index.json

Error downloading https://downloads.arduino.cc/libraries/library_index.json
java.lang.RuntimeException: java.lang.Exception: Error downloading https://downloads.arduino.cc/libraries/library_index.json
	at cc.arduino.contributions.libraries.ui.LibraryManagerUI.lambda$onUpdatePressed$2(LibraryManagerUI.java:207)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.Exception: Error downloading https://downloads.arduino.cc/libraries/library_index.json
	at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:149)
	at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:130)
	at cc.arduino.contributions.JsonDownloader.download(JsonDownloader.java:49)
	at cc.arduino.contributions.GZippedJsonDownloader.download(GZippedJsonDownloader.java:66)
	at cc.arduino.contributions.libraries.LibraryInstaller.updateIndex(LibraryInstaller.java:84)
	at cc.arduino.contributions.libraries.ui.LibraryManagerUI.lambda$onUpdatePressed$2(LibraryManagerUI.java:203)
	... 1 more
Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
	at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1946)
	at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:316)
	at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:310)
	at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1639)
	at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:223)
	at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037)
	at sun.security.ssl.Handshaker.process_record(Handshaker.java:965)
	at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1064)
	at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1367)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1395)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1379)
	at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
	at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
	at sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:162)
	at cc.arduino.utils.network.HttpConnectionManager.makeConnection(HttpConnectionManager.java:155)
	at cc.arduino.utils.network.HttpConnectionManager.makeConnection(HttpConnectionManager.java:106)
	at cc.arduino.utils.network.FileDownloaderCache.updateCacheInfo(FileDownloaderCache.java:184)
	at cc.arduino.utils.network.FileDownloaderCache.getFileCached(FileDownloaderCache.java:153)
	at cc.arduino.utils.network.FileDownloader.downloadFile(FileDownloader.java:167)
	at cc.arduino.utils.network.FileDownloader.download(FileDownloader.java:129)
	at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:147)
	... 6 more
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:397)
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302)
	at sun.security.validator.Validator.validate(Validator.java:262)
	at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
	at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229)
	at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124)
	at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1621)
	... 23 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
	at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
	at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
	at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:392)
	... 29 more
Invalid library found in C:\Users\Eric\Documents\Arduino\libraries\Arduino_LSM6DS3: no headers files (.h) found in C:\Users\Eric\Documents\Arduino\libraries\Arduino_LSM6DS3
Invalid library found in C:\Users\Eric\Documents\Arduino\libraries\EduIntro: no headers files (.h) found in C:\Users\Eric\Documents\Arduino\libraries\EduIntro
Invalid library found in C:\Users\Eric\Documents\Arduino\libraries\WiFiNINA: no headers files (.h) found in C:\Users\Eric\Documents\Arduino\libraries\WiFiNINA

I want to install some libraries from the manage libraries . But i keep getting this error .
Im using the latest Arduino IDE on a Windows 10.
If someone can help me understand this error and has a fix for it , It would be greatly appreciated.

Does this message comes when you start the IDE or when you try to download libraries from the manager?

SathvikHegde:
Does this message comes when you start the IDE or when you try to download libraries from the manager?

Only when i try to download libraries from the manage libraries