Do you have other wallets running with a connection to their networks? Have you made any changes to your computer or routers firewall that might be blocking the connections?
You can grab a list of nodes from https://chainz.cryptoid.info/pot/#!network
Copy and paste the entire list to a "potcoin.conf" file in the same folder as your blockchain, if your on windows its under appdata\roaming, you can browse there in an explorer window by using %appdata% and hitting enter.