Hi Stefan,

This error is most likely caused by a problem with a USB 3G modem driver. Not all 3G modem drivers handle sleep-resume cycles or USB problems well and this may result in a virtual serial port that generates errors. Sometimes the 3G modem driver even changes the virtual serial port number during operation.

If this is indeed the cause the best option is to remove the GSM Modem Gateway from Diafaan SMS Server, restart the computer and add a new GSM Modem Gateway.

A more permanent solution is to update the firmware and modem drivers of the 3G modem or use another type of modem.

Regards,
Henk