Does a Scroll of Protection protect against Wall of Fire?

Question

From the DMG page 199...

Scroll of Protection

Using an action to read the scroll encloses you in a invisible barrier that extends from you to form a 5-foot-radius, 10-foot-high cylinder. For 5 minutes, this barrier prevents creatures of the specified type from entering or affecting anything within the cylinder...

A creature can attempt to overcome the barrier by using an action to make a DC 15 Charisma check. On a success, the creature ceases to be affected by the barrier.

There's a lot of different types of spells, so I want to drill down to a specific example: Assume an efreeti casts Wall of Fire blocking a narrow corridor. Could a PC use a Scroll of Protection (elementals) and then walk through the Wall of Fire without taking damage?

If the above answer is YES: if the efreeti succeeded on its Charisma check to overcome the barrier, would the PC start being subject to damage from the Wall of Fire?

Answer 1

No.

For 5 minutes, this barrier prevents creatures of the specified type from entering or affecting anything within the cylinder...

The efreet is not trying to enter the cylinder. The efreet is casting a spell, but the target of that spell (the point of origin for the wall of fire) is not in the cylinder.

So if the wall is cast outside the protective cylinder and the protectee moves toward the wall: (a) the cylinder moves, per the scroll description, and is not banished by contact with the non-creature wall, and (b) the protectee is now within range of the harmful effects of the wall.

---

Could the efreet cast the wall into the protected cylinder? No: the "cannot effect" language would seem to prevent targeting a point inside the cylinder with a spell.

Answer 2

Yes, a scroll of protection can potentially safeguard against a creature of a certain type, as well as the actions they take to affect the area within the cylinder.

If the PC, buffed with the scroll, entered the wall of fire's damage range cast by the efreeti, he or she would be immune to its effect until the caster uses an action to beat a Charisma check. Though the wall is not a creature it takes concentration from the "forbidden" creature to maintain, and should count as active attempts to affect the cylinder's area.

Wall of fire - pg 285 PHB (Emphasized the relevant part.)
Duration: Concentration, up to 1 minute
[...]
When the wall appears, each creature within its area must make a Dexterity saving throw. On a failed save, a creature takes 5d8 fire damage, or half as much damage on a successful save.

One side of the wall, selected by you when you cast this spell, deals 5d8 fire damage to each creature that ends its turn within 10 feet of that side or inside the wall. [...]

Since wall of fire is a concentration spell with a duration of up to 1 minute and deals damage when it first appears and to creatures that end its turn inside of it (PHB pg 285), the efreeti's spell can still be active and maintained by the time it beats the Charisma check, after which subsequent wall of fire damage will be resolved the normal way, through DEX saves.