No new connection after inserting MTS Mblaze dongle

[Vikash]

I am using ubuntu 16.04 LTS.
Network Manager Version : 1.1.93

Problem :
No new connection showing up after inserting MTS mblaze dongle.

Steps to Reproduce:
1. Insert MTS Mblaze dongle
2. Create new mobile broadband connection.
3. Remove and reinsert dongle
4. Check Available Connections
5. Check Output of command "nmcli --pretty -f all device show"

Expected Results:
The newly created mobile broadband connection should be listed as available.

Actual Results:
The newly created connection does not show up, even though modem manager recognizes device as usb modem.

Output of "nmcli --pretty -f all device show":

===============================================================================
                            Device details (wlp5s0)
===============================================================================
GENERAL.DEVICE: wlp5s0
GENERAL.TYPE: wifi
GENERAL.NM-TYPE: NMDeviceWifi
GENERAL.VENDOR: Intel Corporation
GENERAL.PRODUCT: Wireless 3160 (Dual Band Wireless AC 3160)
GENERAL.DRIVER: iwlwifi
GENERAL.DRIVER-VERSION: 4.4.0-22-generic
GENERAL.FIRMWARE-VERSION: 16.242414.0
GENERAL.HWADDR: 34:E6:AD:D9:91:03
GENERAL.MTU: 0
GENERAL.STATE: 30 (disconnected)
GENERAL.REASON: 42 (The supplicant is now available)
GENERAL.UDI: /sys/devices/pci0000:00/0000:00:1c.5/0000:05:00.0/net/wlp5s0
GENERAL.IP-IFACE:
GENERAL.IS-SOFTWARE: no
GENERAL.NM-MANAGED: yes
GENERAL.AUTOCONNECT: yes
GENERAL.FIRMWARE-MISSING: no
GENERAL.NM-PLUGIN-MISSING: no
GENERAL.PHYS-PORT-ID: --
GENERAL.CONNECTION: --
GENERAL.CON-UUID: --
GENERAL.CON-PATH: --
GENERAL.METERED: unknown
-------------------------------------------------------------------------------
CAPABILITIES.CARRIER-DETECT: no
CAPABILITIES.SPEED: unknown
CAPABILITIES.IS-SOFTWARE: no
-------------------------------------------------------------------------------
WIFI-PROPERTIES.WEP: yes
WIFI-PROPERTIES.WPA: yes
WIFI-PROPERTIES.WPA2: yes
WIFI-PROPERTIES.TKIP: yes
WIFI-PROPERTIES.CCMP: yes
WIFI-PROPERTIES.AP: yes
WIFI-PROPERTIES.ADHOC: yes
WIFI-PROPERTIES.2GHZ: yes
WIFI-PROPERTIES.5GHZ: yes
-------------------------------------------------------------------------------
AP[1].*:
AP[1].SSID: mohit
AP[1].MODE: Infra
AP[1].CHAN: 4
AP[1].RATE: 54 Mbit/s
AP[1].SIGNAL: 70
AP[1].BARS: ▂▄▆_
AP[1].SECURITY: WPA2
-------------------------------------------------------------------------------
AP[2].*:
AP[2].SSID: Sivasai
AP[2].MODE: Infra
AP[2].CHAN: 11
AP[2].RATE: 54 Mbit/s
AP[2].SIGNAL: 47
AP[2].BARS: ▂▄__
AP[2].SECURITY: WPA1 WPA2
-------------------------------------------------------------------------------
CONNECTIONS.AVAILABLE-CONNECTION-PATHS:
-------------------------------------------------------------------------------

===============================================================================
                           Device details (ttyUSB0)
===============================================================================
GENERAL.DEVICE: ttyUSB0
GENERAL.TYPE: cdma
GENERAL.NM-TYPE: NMDeviceModem
GENERAL.VENDOR: ZTE, Incorporated
GENERAL.PRODUCT: ZTE CDMA Tech
GENERAL.DRIVER: option1
GENERAL.DRIVER-VERSION:
GENERAL.FIRMWARE-VERSION:
GENERAL.HWADDR: (unknown)
GENERAL.MTU: 0
GENERAL.STATE: 20 (unavailable)
GENERAL.REASON: 2 (Device is now managed)
GENERAL.UDI: /org/freedesktop/ModemManager1/Modem/0
GENERAL.IP-IFACE:
GENERAL.IS-SOFTWARE: no
GENERAL.NM-MANAGED: yes
GENERAL.AUTOCONNECT: yes
GENERAL.FIRMWARE-MISSING: no
GENERAL.NM-PLUGIN-MISSING: no
GENERAL.PHYS-PORT-ID: --
GENERAL.CONNECTION: --
GENERAL.CON-UUID: --
GENERAL.CON-PATH: --
GENERAL.METERED: unknown
-------------------------------------------------------------------------------
CAPABILITIES.CARRIER-DETECT: no
CAPABILITIES.SPEED: unknown
CAPABILITIES.IS-SOFTWARE: no
-------------------------------------------------------------------------------
CONNECTIONS.AVAILABLE-CONNECTION-PATHS:
-------------------------------------------------------------------------------

===============================================================================
                            Device details (enp2s0)
===============================================================================
GENERAL.DEVICE: enp2s0
GENERAL.TYPE: ethernet
GENERAL.NM-TYPE: NMDeviceEthernet
GENERAL.VENDOR: Realtek Semiconductor Co., Ltd.
GENERAL.PRODUCT: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
GENERAL.DRIVER: r8168
GENERAL.DRIVER-VERSION: 8.041.00-NAPI
GENERAL.FIRMWARE-VERSION:
GENERAL.HWADDR: 30:8D:99:F4:AF:66
GENERAL.MTU: 1500
GENERAL.STATE: 20 (unavailable)
GENERAL.REASON: 2 (Device is now managed)
GENERAL.UDI: /sys/devices/pci0000:00/0000:00:1c.2/0000:02:00.0/net/enp2s0
GENERAL.IP-IFACE:
GENERAL.IS-SOFTWARE: no
GENERAL.NM-MANAGED: yes
GENERAL.AUTOCONNECT: yes
GENERAL.FIRMWARE-MISSING: no
GENERAL.NM-PLUGIN-MISSING: no
GENERAL.PHYS-PORT-ID: --
GENERAL.CONNECTION: --
GENERAL.CON-UUID: --
GENERAL.CON-PATH: --
GENERAL.METERED: unknown
-------------------------------------------------------------------------------
CAPABILITIES.CARRIER-DETECT: yes
CAPABILITIES.SPEED: unknown
CAPABILITIES.IS-SOFTWARE: no
-------------------------------------------------------------------------------
WIRED-PROPERTIES.CARRIER: off
-------------------------------------------------------------------------------
CONNECTIONS.AVAILABLE-CONNECTION-PATHS: /org/freedesktop/NetworkManager/Settings/{3}
CONNECTIONS.AVAILABLE-CONNECTIONS[1]: 007d1c33-1123-46bf-9968-d883d5ba9321 | Wired connection 1
-------------------------------------------------------------------------------

===============================================================================
                              Device details (lo)
===============================================================================
GENERAL.DEVICE: lo
GENERAL.TYPE: loopback
GENERAL.NM-TYPE: NMDeviceGeneric
GENERAL.VENDOR:
GENERAL.PRODUCT:
GENERAL.DRIVER: unknown
GENERAL.DRIVER-VERSION:
GENERAL.FIRMWARE-VERSION:
GENERAL.HWADDR: 00:00:00:00:00:00
GENERAL.MTU: 65536
GENERAL.STATE: 10 (unmanaged)
GENERAL.REASON: 0 (No reason given)
GENERAL.UDI: /virtual/device/placeholder/2
GENERAL.IP-IFACE: lo
GENERAL.IS-SOFTWARE: yes
GENERAL.NM-MANAGED: no
GENERAL.AUTOCONNECT: yes
GENERAL.FIRMWARE-MISSING: no
GENERAL.NM-PLUGIN-MISSING: no
GENERAL.PHYS-PORT-ID: --
GENERAL.CONNECTION: --
GENERAL.CON-UUID: --
GENERAL.CON-PATH: --
GENERAL.METERED: unknown
-------------------------------------------------------------------------------
CAPABILITIES.CARRIER-DETECT: yes
CAPABILITIES.SPEED: unknown
CAPABILITIES.IS-SOFTWARE: yes
-------------------------------------------------------------------------------
CONNECTIONS.AVAILABLE-CONNECTION-PATHS:
-------------------------------------------------------------------------------
IP4.ADDRESS[1]: 127.0.0.1/8
IP4.GATEWAY:
-------------------------------------------------------------------------------
IP6.ADDRESS[1]: ::1/128
IP6.GATEWAY:
-------------------------------------------------------------------------------

USB Modem Details:

running mmcli -L gives :

    Found 1 modems:
        /org/freedesktop/ModemManager1/Modem/0 [ZTEMT INCORPORATED] AC2792

and mmcli -m 0 gives

    /org/freedesktop/ModemManager1/Modem/0 (device id 'bda7d8378866c892ed4c1eed78be4aec3c993c16')
    -------------------------
    Hardware | manufacturer: 'ZTEMT INCORPORATED'
            | model: 'AC2792'
            | revision: 'AC2792YU8AD511'
            | supported: 'cdma-evdo'
            | current: 'cdma-evdo'
            | equipment id: '80A0C53D'
    -------------------------
    System | device: '/sys/devices/pci0000:00/0000:00:14.0/usb1/1-3'
            | drivers: 'option1'
            | plugin: 'ZTE'
            | primary port: 'ttyUSB0'
            | ports: 'ttyUSB0 (at), ttyUSB1 (at), ttyUSB3 (qcdm)'
    -------------------------
    Numbers | own : '8645921832'
    -------------------------
    Status | lock: 'none'
            | unlock retries: 'unknown'
            | state: 'enabled'
            | power state: 'on'
            | access tech: 'unknown'
            | signal quality: '0' (cached)
    -------------------------
    Modes | supported: 'allowed: 2g; preferred: none
            | allowed: 3g; preferred: none
            | allowed: 2g, 3g; preferred: none
            | allowed: 2g, 3g; preferred: 2g
            | allowed: 2g, 3g; preferred: 3g'
            | current: 'allowed: any; preferred: none'
    -------------------------
    Bands | supported: 'unknown'
            | current: 'unknown'
    -------------------------
    IP | supported: 'ipv4'
    -------------------------
    CDMA | meid: 'unknown'
            | esn: '80A0C53D'
            | sid: 'unknown'
            | nid: 'unknown'
            | registration: CDMA1x 'unknown'
            | EV-DO 'unknown'
            | activation: 'unknown'
    -------------------------
    SIM | path: 'none'

    -------------------------
    Bearers | paths: 'none'

Reproducibility:

The problem was solved temporarily when i was out of town for a week and the connection automatically worked in the new location. Now i am back home and the same problem arises again (The mobile broadband connection isn't listed as available)