Changing Phone Number caused SIM7070G to error out?

We finally got the Waveshare SIM7070G set up to send and receive texts, except for a friend who lives further north. We were thinking that maybe it’s because it was being sent from the long default phone number, so we bought a $1/month phone number. I was able to send a text to the new phone number, but it is no longer able to send texts without errors (via AT command tester. See commands below). Does the phone number just need time to “activate” or something?

Checking registration status…

AT+CREG?

+CREG: 0,5

OK
Device is registered and is roaming.

AT+CGREG?

+CGREG: 0,5

OK
Device is registered and is roaming.

Checking SMS Mode…

AT+CMGF?

+CMGF: 1

OK
SMS message for is configured for Text mode
Device is configured for Text mode for SMS.

Encoding set for 7-bit
AT+CSMP=17,167,2,0

OK
Setting Character Set to GSM
AT+CSCS=“GSM”

OK
AT+CMGS="+1414XXXXXXX"

Test Message

+CMS ERROR: 500

Do not change your SMSC or things will not work.

When you purchase a phone number through us it is not like adding another line to an active subscription. That phone number is used to route things through our API and other services, which eventually is passed along to an SMSC or SMPP service, is not directly tied to the SIM itself and by changing things in the SMS configuration it will likely fail.

How would I go about going back to the old SMSC? When I boot up the device it looks like it retains the one that I changed

I think you have already done so but reach out to support@hologram.io and they should be able to look up the correct value to fix the SMSC issue.