In some cases you may receive a CMS Error 500 error message from your modem.
This error message indicates, that for some reason the modem was not able to
deliver the message. This error can happen if:
The phone number you try to send your message to is invalid
There is no network coverage
You don't have enough money on a prepaid subscription
The short message service center of the GSM network operator is temporarily
out of service
The GSM cell is overloaded
If none of these issues have caused this problem, there is not much you can do
to work around this. The following things might help:
1.) Please make sure you use the latest version of Ozeki NG SMS Gateway. The
latest version can be downloaded from the following website:
2.) Enable "slow modem communication" on the "port settings" tab of the
"GSM modem configuration" form.
3.) Change the "HW flow" and "SW flow" settings to "None" on the "port
settings" tab of the "GSM modem configuration" form.
If the problem happens occasionally, you can configure multiple retries for
message delivery on the "Advanced" tab of the "Edit/server preferences" form
by setting the value of the "Max number of tries" field to 6.