diff --git a/src/createRoom.js b/src/createRoom.js
index a39d2c2216..4d59b11656 100644
--- a/src/createRoom.js
+++ b/src/createRoom.js
@@ -212,7 +212,17 @@ export async function _waitForMember(client, roomId, userId, opts = { timeout: 1
  * can encrypt to.
  */
 export async function canEncryptToAllUsers(client, userIds) {
-    const usersDeviceMap = await client.downloadKeys(userIds);
+    let usersDeviceMap;
+    try {
+        usersDeviceMap = await client.downloadKeys(userIds);
+    } catch (ex) {
+       if (ex.httpStatus === 404) {
+            // The endpoint to fetch keys doesn't exist: force unencrypted.
+            // See: https://github.com/vector-im/riot-web/issues/13598
+            return false;
+       }
+       throw ex;
+    }
     // { "@user:host": { "DEVICE": {...}, ... }, ... }
     return Object.values(usersDeviceMap).every((userDevices) =>
         // { "DEVICE": {...}, ... }