It's possible if we are working with AT Command we could get the +CMS ERROR: 302. But what circumstances do I get +CMS ERROR: 302?
CMS ERROR 302 means "Operation not allowed".
Possible reasons for this error are :
(1) The service may be unavailable during that time.
(2) Service provider has locked the service.
(3) Corporate lock is active
(4) Module was powered off by +CPOF, CFUN=0, unplug, or Low battery level
(5) Service not correctly loaded
(6) SIM does not support SMSCB
Hope this helps.