A few things to check when a giffgaff SIM won’t send SMS on one modem but works on another:
• Network mode/bands: set the gateway to 3G/UMTS (not LTE-only), and make sure it supports 900/2100 MHz (O2/giffgaff).
• SIM PIN/lock: disable SIM PIN and verify the device isn’t carrier-locked.
• Signal/registration: check RSSI and registration (AT+CSQ, AT+CREG?, AT+COPS?). If not registered, try manual select to O2 UK.
• SMS settings: many gateways need TEXT mode (AT+CMGF=1). Read/set the SMSC (AT+CSCA? / AT+CSCA="number")—copy the service-centre number from the working modem.
• Storage: ensure SMS memory isn’t full (AT+CPMS?).
• APN/profile: some devices won’t fully attach without a correct profile—use giffgaff APN (typically “giffgaff.com”, user “giffgaff”, pass “password”).
• Credit/account: confirm the line has credit/active bundle; giffgaff can block SMS if the package lapsed.
• Firmware/driver: update the gateway firmware; some builds break SMS on certain modules.
• Swap test: try another known-good SIM in the problem gateway and your giffgaff SIM in a third device to isolate hardware vs. config.
If you can share the module model and the AT log when you run: AT+CFUN?; AT+CSQ; AT+CREG?; AT+COPS?; AT+CMGF?; AT+CSCA?; and the error from AT+CMGS, I can suggest exact commands to fix it.
Tra l’altro, se stai preparando un look per la sera, puoi dare un tocco moderno con gli
abiti asimmetrici, linee dinamiche che slanciano e funzionano bene sia con tacchi sia con sandali.