Q:

VPN service connection failed because the VPN service failed to start

I'm trying to connect to my universities VPN on Ubuntu. Unfortunately they don't offer any guidance on Linux (I'm on Ubuntu 16.04) VPN setup, only Windows and Mac, so I'm trying to connect from the information they provide for them.
Here is their online guide - https://www.stir.ac.uk/is/student/it/connect/off-campus/
Going by the Mac installation guide, it states:
"VPN Type: L2TP over IPsec" .. so I've run sudo apt-get install network-manager-l2tp-gnome, restarted Ubuntu and now I have the option to create a Layer 2 Tunneling Protocol (L2TP) connection.
I've entered the gateway and username as they instruct. As they also request "over IPsec" I've checked the box, IPsec Settings... > "Enable IPsec tunnel to L2TP host", I've also entered "secret" in the Pre shared key box. By the way, I also tried to connect prior to setting these but it didn't work, and doesn't work now I've entered them either.
If it helps, here is the log from sudo tail -f /var/log/syslog:
Mar  1 15:29:32 martyn-Lenovo-B590 NetworkManager[954]: <info>  [1519918172.6221] audit: op="connection-activate" uuid="9f1fcb5e-7d9b-41e2-9637-2a9545283b10" name="UoS VPN" pid=2301 uid=1000 result="success"
Mar  1 15:29:32 martyn-Lenovo-B590 NetworkManager[954]: <info>  [1519918172.6310] vpn-connection[0x27291e0,9f1fcb5e-7d9b-41e2-9637-2a9545283b10,"UoS VPN",0]: Started the VPN service, PID 4452
Mar  1 15:29:32 martyn-Lenovo-B590 NetworkManager[954]: <info>  [1519918172.6452] vpn-connection[0x27291e0,9f1fcb5e-7d9b-41e2-9637-2a9545283b10,"UoS VPN",0]: Saw the service appear; activating connection
Mar  1 15:29:32 martyn-Lenovo-B590 gnome-session[1999]: Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.
Mar  1 15:29:37 martyn-Lenovo-B590 NetworkManager[954]: <info>  [1519918177.6835] keyfile: update /etc/NetworkManager/system-connections/UoS VPN (9f1fcb5e-7d9b-41e2-9637-2a9545283b10,"UoS VPN")
Mar  1 15:29:37 martyn-Lenovo-B590 NetworkManager[954]: <info>  [1519918177.6915] vpn-connection[0x27291e0,9f1fcb5e-7d9b-41e2-9637-2a9545283b10,"UoS VPN",0]: VPN connection: (ConnectInteractive) reply received
Mar  1 15:29:37 martyn-Lenovo-B590 NetworkManager[954]: nm-l2tp[4452] <info>  ipsec enable flag: yes
Mar  1 15:29:37 martyn-Lenovo-B590 NetworkManager[954]: ** Message: Check port 1701
Mar  1 15:29:37 martyn-Lenovo-B590 NetworkManager[954]: ** Message: Can't bind to port 1701
Mar  1 15:29:37 martyn-Lenovo-B590 NetworkManager[954]: nm-l2tp[4452] <warn>  L2TP port 1701 is busy, using ephemeral.
Mar  1 15:29:37 martyn-Lenovo-B590 NetworkManager[954]: nm-l2tp[4452] <info>  starting ipsec
Mar  1 15:29:37 martyn-Lenovo-B590 NetworkManager[954]: Stopping strongSwan IPsec failed: starter is not running
Mar  1 15:29:39 martyn-Lenovo-B590 NetworkManager[954]: Starting strongSwan 5.3.5 IPsec [starter]...
Mar  1 15:29:39 martyn-Lenovo-B590 NetworkManager[954]: Loading config setup
Mar  1 15:29:39 martyn-Lenovo-B590 NetworkManager[954]: Loading conn '9f1fcb5e-7d9b-41e2-9637-2a9545283b10'
Mar  1 15:29:39 martyn-Lenovo-B590 NetworkManager[954]: found netkey IPsec stack
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[DMN] Starting IKE charon daemon (strongSwan 5.3.5, Linux 4.4.0-116-generic, x86_64)
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[CFG] loading ca certificates from '/etc/ipsec.d/cacerts'
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[CFG] loading aa certificates from '/etc/ipsec.d/aacerts'
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[CFG] loading ocsp signer certificates from '/etc/ipsec.d/ocspcerts'
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[CFG] loading attribute certificates from '/etc/ipsec.d/acerts'
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[CFG] loading crls from '/etc/ipsec.d/crls'
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[CFG] loading secrets from '/etc/ipsec.secrets'
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[CFG] loading secrets from '/etc/ipsec.d/nm-l2tp-ipsec-9f1fcb5e-7d9b-41e2-9637-2a9545283b10.secrets'
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[CFG]   loaded IKE secret for %any
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[LIB] loaded plugins: charon test-vectors aes rc2 sha1 sha2 md4 md5 random nonce x509 revocation constraints pubkey pkcs1 pkcs7 pkcs8 pkcs12 pgp dnskey sshkey pem openssl fips-prf gmp agent xcbc hmac gcm attr kernel-netlink resolve socket-default connmark stroke updown
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[LIB] dropped capabilities, running as uid 0, gid 0
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 00[JOB] spawning 16 worker threads
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 13[CFG] received stroke: add connection '9f1fcb5e-7d9b-41e2-9637-2a9545283b10'
Mar  1 15:29:39 martyn-Lenovo-B590 charon: 13[CFG] added configuration '9f1fcb5e-7d9b-41e2-9637-2a9545283b10'
Mar  1 15:29:40 martyn-Lenovo-B590 charon: 01[CFG] rereading secrets
Mar  1 15:29:40 martyn-Lenovo-B590 charon: 01[CFG] loading secrets from '/etc/ipsec.secrets'
Mar  1 15:29:40 martyn-Lenovo-B590 charon: 01[CFG] loading secrets from '/etc/ipsec.d/nm-l2tp-ipsec-9f1fcb5e-7d9b-41e2-9637-2a9545283b10.secrets'
Mar  1 15:29:40 martyn-Lenovo-B590 charon: 01[CFG]   loaded IKE secret for %any
Mar  1 15:29:40 martyn-Lenovo-B590 NetworkManager[954]: nm-l2tp[4452] <info>  Spawned ipsec up script with PID 4531.
Mar  1 15:29:40 martyn-Lenovo-B590 charon: 11[CFG] received stroke: initiate '9f1fcb5e-7d9b-41e2-9637-2a9545283b10'
Mar  1 15:29:40 martyn-Lenovo-B590 charon: 07[IKE] initiating Main Mode IKE_SA 9f1fcb5e-7d9b-41e2-9637-2a9545283b10[1] to 139.153.12.200
Mar  1 15:29:40 martyn-Lenovo-B590 charon: 07[ENC] generating ID_PROT request 0 [ SA V V V V ]
Mar  1 15:29:40 martyn-Lenovo-B590 charon: 07[NET] sending packet: from 192.168.1.134[500] to 139.153.12.200[500] (248 bytes)
Mar  1 15:29:44 martyn-Lenovo-B590 charon: 02[IKE] sending retransmit 1 of request message ID 0, seq 1
Mar  1 15:29:44 martyn-Lenovo-B590 charon: 02[NET] sending packet: from 192.168.1.134[500] to 139.153.12.200[500] (248 bytes)
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: nm-l2tp[4452] <warn>  Timeout trying to establish IPsec connection
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: nm-l2tp[4452] <info>  Terminating ipsec script with PID 4531.
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: Stopping strongSwan IPsec...
Mar  1 15:29:50 martyn-Lenovo-B590 charon: 00[DMN] signal of type SIGINT received. Shutting down
Mar  1 15:29:50 martyn-Lenovo-B590 charon: 00[IKE] destroying IKE_SA in state CONNECTING without notification
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: initiating Main Mode IKE_SA 9f1fcb5e-7d9b-41e2-9637-2a9545283b10[1] to 139.153.12.200
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: generating ID_PROT request 0 [ SA V V V V ]
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: sending packet: from 192.168.1.134[500] to 139.153.12.200[500] (248 bytes)
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: sending retransmit 1 of request message ID 0, seq 1
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: sending packet: from 192.168.1.134[500] to 139.153.12.200[500] (248 bytes)
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: destroying IKE_SA in state CONNECTING without notification
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: nm-l2tp[4452] <warn>  Could not establish IPsec tunnel.
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: (nm-l2tp-service:4452): GLib-GIO-CRITICAL **: g_dbus_method_invocation_take_error: assertion 'error != NULL' failed
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: <info>  [1519918190.9294] vpn-connection[0x27291e0,9f1fcb5e-7d9b-41e2-9637-2a9545283b10,"UoS VPN",0]: VPN plugin: state changed: stopped (6)
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: <info>  [1519918190.9315] vpn-connection[0x27291e0,9f1fcb5e-7d9b-41e2-9637-2a9545283b10,"UoS VPN",0]: VPN plugin: state change reason: unknown (0)
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: <info>  [1519918190.9339] vpn-connection[0x27291e0,9f1fcb5e-7d9b-41e2-9637-2a9545283b10,"UoS VPN",0]: VPN service disappeared
Mar  1 15:29:50 martyn-Lenovo-B590 NetworkManager[954]: <warn>  [1519918190.9360] vpn-connection[0x27291e0,9f1fcb5e-7d9b-41e2-9637-2a9545283b10,"UoS VPN",0]: VPN connection: failed to connect: 'Message recipient disconnected from message bus without replying'

I did try googling some of the errors but didn't find anything that offered anything that seemed helpful, although it is a little over my head.
Is there anything I may be missing? Thanks in advance. 

A:

The VPN server you are connecting to (extvpn.stir.ac.uk) is only proposing weak algorithms, see README.md file:

https://github.com/nm-l2tp/network-manager-l2tp#issue-with-vpn-servers-only-proposing-ipsec-ikev1-weak-legacy-algorithms

You'll need to enter the following in the IPsec Options dialog box advanced section:

Phase1 Algorithms: aes-sha1-modp1024
Phase2 Algorithms: aes-sha1

You might also need to stop the system xl2tpd, see README.md file :

https://github.com/nm-l2tp/network-manager-l2tp#issue-with-not-stopping-system-xl2tpd-service

