I am working with the testnet. I downloaded the bitcoin-core application on Linux and I am running the version Bitcoin Core version v0.12.1.0-g9779e1e (64-bit) I was able to download the bitcoin block, recently its no longer syncing with the bitcoin network. Its showing 3 days behind and 0 active connection to the bitcoin network. How can I fix the issue. I want to connect to the testnet. I tried to change the network settings in the application. Still its not working.