Current bitcoin-master on testnet, `maxconnections=8` in the config file. Running in VM that doesn't have public IP and is not reachable from the Internet.

Wait until you have 8 peers.

```
telnet localhost 18333
```

It will result in:

```
Assertion failed: (nMaxInbound > 0), function AcceptConnection, file net.cpp, line 973.
```

First found in https://github.com/bitcoin/bitcoin/pull/8996, but can be reproduced on master.

}
                    }
                    if (fDelete)
                    {
                        vNodesDisconnected.remove(pnode);
                        DeleteNode(pnode);
                    }
                }
            }
        }
        if(vNodes.size() != nPrevNodeCount) {
            nPrevNodeCount = vNodes.size();
            if(clientInterface)
                clientInterface->NotifyNumConnectionsChanged(nPrevNodeCount);
        }
        
        
        
        struct timeval timeout;
        timeout.tv_sec  = 0;
        timeout.tv_usec = 50000; 
        fd_set fdsetRecv;
        fd_set fdsetSend;
        fd_set fdsetError;
        FD_ZERO(&fdsetRecv);
        FD_ZERO(&fdsetSend);
        FD_ZERO(&fdsetError);
        SOCKET hSocketMax = 0;
        bool have_fds = false;
        BOOST_FOREACH(const ListenSocket& hListenSocket, vhListenSocket) {