EG21-G Restarts Every 90 Seconds

I am finding that when the modem has a UICC installed (or the eUICC eSIM profile is enabled) and the modem cannot register with the network, that the modem will restart every 90 seconds.

However, when the modem is able to register with the network or the UICC is removed (or the eUICC eSIM profile is disabled), the modem does not restart.

How can I change the behaviour so that the modem does not restart autonomously?

Quectel EG21-G
Revision: EG21GGBR07A09M1G

Dear Ron-Mcleod,
Thanks for your inquiry in Quectel forum.
About your issue, it is better to check whether the power supply is stable enough, you can monitor it. And you can try to set AT+CFUN=4 to let the module enter into airplane mode to confirm whether it is still have such issues. Thanks!