A person should always be careful with the Mincha prayer, for Elijah was only answered at the time of Mincha.

924. Clarifications on Zohar II 156a: Timing of Mincha, Nighttime Judgments, and Moses' Passing הבהרות על זהר חלק ב דף קנ"ו א, זמן מנחה, דיני לילה ופטירת משה