lymht yjbb lyabwm yl ftahla — not clear.
Given the time, maybe it’s simply ROT13: t (20) → g (7) h (8) → u (21) m (13) → z (26) y (25) → l (12) l (12) → y (25) thmyl bbjy mwbayl ly alhatf
t (20) → o (15) h (8) → c (3) m (13) → h (8) y (25) → t (20) l (12) → g (7) lymht yjbb lyabwm yl ftahla — not clear
But the phrase bbjy — if b→n (Atbash), b→n, j→q, y→b → nq b ? No. y→b → nq b ? No.