Common causes of generation failures include: (1) prompt containing restricted content — rephrase to avoid policy violations; (2) temporary server issues — retry after a minute; (3) account credit balance insufficient — check your credit balance in settings; (4) unsupported characters or extremely long prompts — keep prompts under 500 characters for best results. If a failure occurs due to a system error (not a policy violation), credits are automatically returned to your account. Contact support if failures persist.