I can't find a forum for the AirCard 781S. Can someone please direct me to the right forum? I'm posting here because it's semi-related and generic.

My problem is this: The device is working properly, and connects to the AT&T Wireless network flawlessly (I love this thing). However, when I try to connect a PPTP VPN (Dell XPS12 / Windows 8.1 Pro to Cisco) via the AirCard, it won't connect (typical 619 error). I think that either AT&T started blocking a new port or protocol, or the last firmware update broke it, because it used to work (stopped working within the last month or 2).
Also, if I connect the same DellXPS12 laptop to my HTC Phone with Internet Sharing (on T-Mobile network), the EXACT SAME VPN CONNECTION WORKS FLAWLESSLY. The VPN also works from other Wi-Fi Internet connections like coffee shops, hotel rooms, etc.
I've spent several hours going through the RAS*.LOG files in \windows\tracing, and found that connections that work go through "rasman" states 1-6, then 10,6,18,6,14,24,8192. Then the VPN is connected. With this device (on the AT&T network), the "rasman" states never progress beyond 6. I'm going to keep looking, but I'm sure there will be nothing that I can do on "my side." I already deleted the Wi-Fi profile per the AT&T esupport page recommendation. I also called AT&T tech support, and they said as long as it connects to the cell tower, their troubleshooting is exhausted.

I need HELP!! If this thing didn't work with my VPN, I would have returned it immediately! It did work, but stopped working. I'd like to try the prior version of the firmware, but I can't find any prior versions.

Thanks in advance for any help you can offer.

Here is all of the device info (from the "about" link). A few identifying values changed to **.

Account Details
Wireless number: 1***39122**
MAC Address:: 84-DB-2F-45-08-3B

IMEI: 0138040000468**

FSN: GJ**33055103**
ICCID: 8**141032766527730**

Wi-Fi Details

Wi-Fi name:: UNITE-083B

Wi-Fi password:: (default)
MAC Address:: 84-DB-2F-45-08-3B
IP Address: 10.115.30.66
Encryption: WPA2_Personal_AES
Wi-Fi Devices: 1
Max Wi-Fi Devices: 15
Max Guest Wi-Fi Devices : 0
Wi-Fi Range: Short
Broadcast Network Name: On

Firmware

Firmware Version: NTG9X25C_01.00.49.03
Firmware Build Date: 03/14/14
Web App Version: AC781S_03.02.69.00
Bootloader Version: NTG9X25C_01.00.49.03

Device

Model: AirCard 781S
AT&T Unite Pro Manager:: http://attunitepro
Firmware Version: NTG9X25C_01.00.49.03
Firmware Build Date: 03/14/14
PRI Version: 02.03
Power State: Online
Current temperature: 30Â°C
Current voltage: 3882mV
Battery charge level: 68%
Battery status: Normal
Battery temperature: 29

Network Status

Status: Connected
Signal Strength: 3
RSRP: -97
RSRQ: -8

IMEI: 0138040000468**

Wireless number: 1***39122**
Current radio band: LTE B17
Quality: 40
PS service type: LTE
Network selection mode: Auto
Country: USA
Roaming: false
Network: AT&T
MCC: 310
MNC: 410
LAC: 16656
RAC: 14
Cell ID: 53836047
Channel Number: 16
MNC format: 3
PLMN service error bit mask: 0
IP Address: 10.115.30.66

Forum Discussion

AirCard 781S VPN problem - Which Forum should I use?