In the course of localising an app for the Japanese language I have been tasked with translating the Google-style error string "Oops", which will presumably be used as in
Please check your password and try again
Presuming we want to preserve this conversational interface style (such is the brief), would
しまった be an appropriate translation?
Given that this app will be used by children, I would like to know if this is considered acceptable language or not. If not, are there some good "family-friendly" alternatives?