Fixing blockcing nil pointer

protocol/connections/engine.go

@@ -122,7 +122,7 @@ func (e *engine) eventHandler() {
 		case event.BlockPeer:
 			e.blocked.Store(ev.Data[event.RemotePeer], true)
 			connection, err := e.service.GetConnection(ev.Data[event.RemotePeer])
-			if err != nil {
+			if connection != nil && err == nil {
 				connection.Close()
 			}
 		case event.ProtocolEngineStartListen: