troubleshooting Chatty / modem? no SMS outbound

[vap0rtranz]

What operating system and which desktop are you using.?

I've tested:
Mobian Bookworm
PostmarketOS (v21.12.1).

I've also tested 2 MVNOs via 2 SIM cards:
USMobile (running off T-Mobile in my location)
Cellcom (running off Verizon)

Combos of the above all yield the same symptom: no outbound SMS.

Poking around a lot on this, I found this Issue already filed SMS send don't work in 4G-mode:
https://github.com/Biktorgj/pinephone_mo.../issues/40

I tried the 2 workarounds in that ^ issue:

Code:

{ cmd = "QCFG", subcmd = "ims", expect = "2" },

and (separately):

Code:

AT+CGSMS=3
... # retest
AT+CGSMS=1
... # retest

And another issue filed in Mobian about configuring the modem settings to be compatible with various carriers:
https://gitlab.com/mobian1/issues/-/issues/254

I'll retry to double check that I didn't fat finger a reconfig.

FWIW: the modem is more stable on Cellcom; on USMobile, the modem frequently unregisters & re-registers whether 4G|3G|2G preferred, and does that consistently on SMS send. So do folks think a newer modem firmware would stabilize USMobile ??  I'm on stock original for PPv1.2a (the PostmarketOS CE).

P.S.  I've ordered a new Ting SM to teston them.