V1040 SMS block

[Vidmas30]

Good morning,

 We have a V1040 PLC with attached Cinterion M66i GSM modem. It must send SMS to 1-5 personel. There's a separate window to put in telephone numbers ( to assigned MI's that are assigned to phone book).  We put 3 numbers (2 left blank) and strange things happen - sometimes all 3 numbers get SMS, sometimes just 2 of the, sometimes 1. Tried to init (prepare) modem with different AT commands several times, but it seems like a problem is with V1040 and not with modem. Tried to put in all 5 numbers, but result is the same - sometimes we get all 5 SMS, sometimes 1, sometimes 2... The 1st phone number gets all the time, but the rest sometimes get sometimes not. What is the problem? Thank you!