diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index 18e2da9a31..ad33823c96 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -423,6 +423,8 @@
     "Upgrade your %(brand)s": "Upgrade your %(brand)s",
     "A new version of %(brand)s is available!": "A new version of %(brand)s is available!",
     "Guest": "Guest",
+    "The person who invited you already left the room.": "The person who invited you already left the room.",
+    "The person who invited you already left the room, or their server is offline.": "The person who invited you already left the room, or their server is offline.",
     "There was an error joining the room": "There was an error joining the room",
     "Sorry, your homeserver is too old to participate in this room.": "Sorry, your homeserver is too old to participate in this room.",
     "Please contact your homeserver administrator.": "Please contact your homeserver administrator.",
diff --git a/src/stores/RoomViewStore.js b/src/stores/RoomViewStore.js
index 6e5007895c..4f560e1fab 100644
--- a/src/stores/RoomViewStore.js
+++ b/src/stores/RoomViewStore.js
@@ -265,10 +265,20 @@ class RoomViewStore extends Store {
             });
             let msg = err.message ? err.message : JSON.stringify(err);
             console.log("Failed to join room:", msg);
-            if (err.name === "ConnectionError") {
+            if (err.httpStatus === 404) {
+                const invitingUserId = this._getInvitingUserId(this._state.roomId);
+                // only provide a better error message for invites
+                if (invitingUserId) {
+                    // if the inviting user is on the same HS, there can only be one cause: they left.
+                    if (invitingUserId.endsWith(`:${MatrixClientPeg.get().getDomain()}`)) {
+                        msg = _t("The person who invited you already left the room.");
+                    } else {
+                        msg = _t("The person who invited you already left the room, or their server is offline.");
+                    }
+                }
+            } else if (err.name === "ConnectionError") {
                 msg = _t("There was an error joining the room");
-            }
-            if (err.errcode === 'M_INCOMPATIBLE_ROOM_VERSION') {
+            } else if (err.errcode === 'M_INCOMPATIBLE_ROOM_VERSION') {
                 msg = <div>
                     {_t("Sorry, your homeserver is too old to participate in this room.")}<br />
                     {_t("Please contact your homeserver administrator.")}
@@ -282,6 +292,16 @@ class RoomViewStore extends Store {
         });
     }
 
+    _getInvitingUserId(roomId) {
+        const cli = MatrixClientPeg.get();
+        const room = cli.getRoom(roomId);
+        if (room && room.getMyMembership() === "invite") {
+            const myMember = room.getMember(cli.getUserId());
+            const inviteEvent = myMember ? myMember.events.member : null;
+            return inviteEvent && inviteEvent.getSender();
+        }
+    }
+
     _joinRoomError(payload) {
         this._setState({
             joining: false,