This is my only serious problem with FrontlineSMS and one which makes it useless for unattended operation:
At seemingly random intervals, my modem (Huawei E170) stops sending and/or receiving. Without a constant flow of messages, it's hard to tell when it happens.
I thought that perhaps it was just a funny problem with that model modem, but I haven't seen any other comments to that effect. Furthermore, the same thing happens even to the clickatell interface. Suddenly it will just stop sending. It might simply keep the msg status as Pending, or show an error, and (I'm not sure) may even show the messages as sent. But they are not. (This is without my making any Clickatell account changes, which will also break the HTTPS connection.)
In both cases, if I "disconnect" the device using the phone panel and reconnect it, the messages start flowing again, including backed-up incoming messages.
Any ideas what could be causing this? A workaround, satisfactory in my case, would be to automatically disconnect and reconnect the modem every 10 minutes. Otherwise, I know the system will not keep working for more than some minutes up to an hour or two.