HL7648 cannot call certain numbers

“Your call cannot be completed as dialed. Please check the number and dial again.”

For 2 specific numbers. These numbers work on other phones. One number is a customer service number 1-484-254-5555. The syntax I use is “ATD14842545555;”

I have tried the number without the leading ‘1’ and tried prefixing it with a ‘+’. Is there any debug info I can find on this?

You can set AT+CSTA=145 and then prefixing the number with a ‘+’

I did: “AT+CSTA=145”
I verified it was set to that.
then “ATD+14842545555;”

I still get the same “Your number cannot be completed as dialed”

Have you tried other international phone numbers? Was it successful?

I am in the USA and these are USA numbers. The one above is to ionos.com customer support. Another number that doesn’t work is someone I know. I can put the sim card into another phone and that phone will dial those numbers. Other phone numbers work fine on this module,

HL7648 supports only VoLTE but not voice call. Please make sure VoLTE is allowed in the service subscription.

VOLTE is enabled and works fine on this module for most numbers. One thing that might be a clue. When I move the SIM card into another phone, the other phone also cannot dial that number the first time, but then it works when I retry it. Putting the SIM back in this HL7648 module, the old problem is back. This problem might be a configuration issue between the module and the SIM.

Also if VoLTE was not enabled, then I would not hear the message.

My problem is occurring with SIM is for an MVNO using AT&T network. I went to an AT&T brick-and-mortar store and borrowed an AT&T SIM. It worked fine to call the above problem number. There is some problem regarding the MVNO SIM I am using with this modem module, and it doesn’t happen if I use the AT&T SIM. I have contacted the MVNO regarding this.