Failed to Join Session in Elden Ring Nightreign: A Layered Fix List That Actually Ends the Loop

You picked Nightreign expecting to coop with two friends and the game rejects the invite with "Failed to join session." You retry, one of you gets in, the third doesn't. You quit, requeue, get a different combination of who works. That is not random. Nightreign uses peer-to-peer connections between the three players, and P2P is unforgiving: if any leg of the three-way handshake fails, the session fails. The fix depends on which leg is breaking.

What the Error Actually Represents

There's no dedicated matchmaking server sitting between you and your friends in a Nightreign session. The game tries to open direct connections between all party members. That means three things need to line up:

• Every player's NAT has to allow inbound P2P traffic (or at least be permissive enough that hole-punching works)
• The route between each pair of players has to be functional and not blocked by a firewall or ISP
• The game clients all need to be on the same version and connecting to a compatible region

When "Failed to join session" appears, one of those three is failing. Diagnosing which one saves you from cycling through irrelevant fixes.

Layer 1: Check NAT Before Anything Else

NAT type is the single most common cause. Strict NAT on any one player in the group can block the session for everyone. Check yours first because it's a two-minute test.

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