This might be a bit old but I just encountered the same problem and it turns out that on the corporate network there was a self signed root SSL certificate.
In order to overcome this problem I had to add the SSL into the JVM keystore as described here
This looks like a Java truststore issue to me. If you had overwritten anything in the JVM installation, it may be affecting your connection to Salesforce.
I have resolved this issue follow the below steps.
Go to Eclipse IDE Windows → Preferences → Network Connections and set Active Provider to Direct.
This issue is related to the Eclipse IDE Network Connections, i found this workaround from below Link