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 (!pnode->fDisconnect)
                                LogPrint("net", "socket closed\n");
                            pnode->CloseSocketDisconnect();
                        }
                        else if (nBytes < 0)
                        {
                            
                            int nErr = WSAGetLastError();
                            if (nErr != WSAEWOULDBLOCK && nErr != WSAEMSGSIZE && nErr != WSAEINTR && nErr != WSAEINPROGRESS)
                            {
                                if (!pnode->fDisconnect)
                                    LogPrintf("socket recv error %s\n", NetworkErrorString(nErr));
                                pnode->CloseSocketDisconnect();
                            }
                        }
                    }
                }
            }
            
            
            
            if (pnode->hSocket == INVALID_SOCKET)
                continue;
            if (FD_ISSET(pnode->hSocket, &fdsetSend))
            {
                TRY_LOCK(pnode->cs_vSend, lockSend);
                if (lockSend) {
                    size_t nBytes = SocketSendData(pnode);