Unable to download driver for ESP8266 through Arduino

When I go to Boards and search 8266 I get the 8266 Community. I select more info and then opt to install. Keep getting "unable to download" error. Help please

Please post the URL you have in File > Preferences > Additional Boards Manager URLs.

Please post the full and exact text of the error.

After you get the error and click the "Close" button in Boards Manager, do you see any text in the black console window at the bottom of the Arduino IDE window? If so, please copy and paste the full text here. You might need to scroll the console window up to see the full text.

URL: http://arduino.esp8266.com/stable/package_esp8266com_index.json

error downloading https://github.com/esp8266/Arduino/releases/download/2.5.5/esp8266-2.5.2.zip

Black screen:
Error downloading https://github.com/esp8266/Arduino/releases/download/2.5.2/esp8266-2.5.2.zip
java.lang.RuntimeException: java.lang.Exception: Error downloading https://github.com/esp8266/Arduino/releases/download/2.5.2/esp8266-2.5.2.zip
at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onInstallPressed$1(ContributionManagerUI.java:176)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.Exception: Error downloading https://github.com/esp8266/Arduino/releases/download/2.5.2/esp8266-2.5.2.zip
at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:131)
at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:69)
at cc.arduino.contributions.packages.ContributionInstaller.install(ContributionInstaller.java:102)
at cc.arduino.contributions.packages.ui.ContributionManagerUI.lambda$onInstallPressed$1(ContributionManagerUI.java:173)
... 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:1959)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:302)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:296)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1514)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1026)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:961)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1072)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1385)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1397)
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:153)
at cc.arduino.utils.network.FileDownloader.downloadFile(FileDownloader.java:170)
at cc.arduino.utils.network.FileDownloader.download(FileDownloader.java:128)
at cc.arduino.contributions.DownloadableContributionsDownloader.download(DownloadableContributionsDownloader.java:129)
... 4 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:260)
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:1496)
... 17 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)
... 23 more

Which version of the Arduino IDE are you using?

Which operating system are you using?

The person I purchased the 8266 from said to use 1.4.8 I'm running Windows 7 Pro

There is no Arduino IDE version 1.4.8. The version numbers jumped from 1.0.6 to 1.5.0.

I'm sorry. It's 1.8.4

Are you able to open https://github.com/esp8266/Arduino/releases/download/2.5.2/esp8266-2.5.2.zip in your browser?

The error seems to imply that it doesn't trust the cert being presented by the server...

Is there anything weird about your connection?

Yep. Work firewall. Thank you for all of your help. Frustrating.

Hi. Just to make sure I understand: are you saying that the problem ended up being caused by the firewall on the network at your work and the error went away after you connected to the Internet through a different network?

If so, congratulations on solving the problem!

If not, we'll continue trying to help you find a solution.