Cannot open Eclipse Marketplace | Cannot install remote marketplace locations: Connection failed

Question

I am getting consistent problem in using Eclipse Marketplace. I am using Eclipse Neon. I am using broadband internet connection and my network configuration for Eclipse is native.

The error is:

Cannot open Eclipse Marketplace
  Cannot install remote marketplace locations: Connection failed

    This is most often caused by a problem with your internet connection. Please check your internet connection and retry.
    Cannot complete request to http://marketplace.eclipse.org/catalogs/api/p: Unable to read repository at http://marketplace.eclipse.org/catalogs/api/p.
  Address family not supported by protocol family: connect
Connection failed

This is most often caused by a problem with your internet connection. Please check your internet connection and retry.
Address family not supported by protocol family: connect

Screenshot of error:

Answer 1

Navigate to Windows->Preferences->General->Network Connections->Set Active Provider to Manual->Schema to HTTPS,HTTP,SOCKS->Click OK->Restart Eclipse

Answer 2

In my case, it's just proxy information:

Window -> Preferences -> Network Connections

• Active Provider: Manual
• HTTP : with proxy value
• HTTPS : with proxy value
• SOCKS : without proxy value

Done.

Answer 3

Solved it. Follow following steps:-

1. Open command prompt.
2. Right click on top left of command prompt, select properties, and enable quick edit mode.
3. Type following line on cmd:- setx _JAVA_OPTIONS -Djava.net.preferIPv4Stack=true, Hit enter.
4. cmd will prompt:- SUCCESS: Specified value was saved.

Restart eclipse.