diff --git a/src/matrix/Session.js b/src/matrix/Session.js
index c80cf527..f82ad555 100644
--- a/src/matrix/Session.js
+++ b/src/matrix/Session.js
@@ -81,16 +81,20 @@ export class Session {
             hsApi: this._hsApi,
             encryptDeviceMessage: async (roomId, userId, deviceId, message, log) => {
                 if (!this._deviceTracker || !this._olmEncryption) {
-                    throw new Error("encryption is not enabled");
+                    log.set("encryption_disabled", true);
+                    return;
                 }
                 const device = await log.wrap("get device key", async log => {
-                    return this._deviceTracker.deviceForId(userId, deviceId, this._hsApi, log);
+                    const device = this._deviceTracker.deviceForId(userId, deviceId, this._hsApi, log);
+                    if (!device) {
+                        log.set("not_found", true);
+                    }
+                    return device;
                 });
-                if (!device) {
-                    throw new Error(`Could not find device key ${deviceId} for ${userId} in ${roomId}`);
+                if (device) {
+                    const encryptedMessages = await this._olmEncryption.encrypt(message.type, message.content, [device], this._hsApi, log);
+                    return encryptedMessages;
                 }
-                const encryptedMessages = await this._olmEncryption.encrypt(message.type, message.content, [device], this._hsApi, log);
-                return encryptedMessages;
             },
             storage: this._storage,
             webRTC: this._platform.webRTC,
diff --git a/src/matrix/calls/group/GroupCall.ts b/src/matrix/calls/group/GroupCall.ts
index b2b52e9b..ddc0b517 100644
--- a/src/matrix/calls/group/GroupCall.ts
+++ b/src/matrix/calls/group/GroupCall.ts
@@ -55,7 +55,7 @@ function getDeviceFromMemberKey(key: string): string {
 
 export type Options = Omit<MemberOptions, "emitUpdate" | "confId" | "encryptDeviceMessage"> & {
     emitUpdate: (call: GroupCall, params?: any) => void;
-    encryptDeviceMessage: (roomId: string, userId: string, deviceId: string, message: SignallingMessage<MGroupCallBase>, log: ILogItem) => Promise<EncryptedMessage>,
+    encryptDeviceMessage: (roomId: string, userId: string, deviceId: string, message: SignallingMessage<MGroupCallBase>, log: ILogItem) => Promise<EncryptedMessage | undefined>,
     storage: Storage,
     logger: ILogger,
 };
diff --git a/src/matrix/calls/group/Member.ts b/src/matrix/calls/group/Member.ts
index 6a8158b6..4c30a6cf 100644
--- a/src/matrix/calls/group/Member.ts
+++ b/src/matrix/calls/group/Member.ts
@@ -36,7 +36,7 @@ export type Options = Omit<PeerCallOptions, "emitUpdate" | "sendSignallingMessag
     // local session id of our client
     sessionId: string,
     hsApi: HomeServerApi,
-    encryptDeviceMessage: (userId: string, deviceId: string, message: SignallingMessage<MGroupCallBase>, log: ILogItem) => Promise<EncryptedMessage>,
+    encryptDeviceMessage: (userId: string, deviceId: string, message: SignallingMessage<MGroupCallBase>, log: ILogItem) => Promise<EncryptedMessage | undefined>,
     emitUpdate: (participant: Member, params?: any) => void,
 }
 
diff --git a/src/matrix/e2ee/DeviceTracker.js b/src/matrix/e2ee/DeviceTracker.js
index 49d9ffab..0d0b0e8b 100644
--- a/src/matrix/e2ee/DeviceTracker.js
+++ b/src/matrix/e2ee/DeviceTracker.js
@@ -338,10 +338,13 @@ export class DeviceTracker {
             const verifiedKeysPerUser = log.wrap("verify", log => this._filterVerifiedDeviceKeys(deviceKeyResponse["device_keys"], log));
             //// END EXTRACT
 
-            // there should only be one device in here, but still check the HS sends us the right one
             const verifiedKeys = verifiedKeysPerUser
                 .find(vkpu => vkpu.userId === userId).verifiedKeys
                 .find(vk => vk["device_id"] === deviceId);
+            // user hasn't uploaded keys for device?
+            if (!verifiedKeys) {
+                return undefined;
+            }
             device = deviceKeysAsDeviceIdentity(verifiedKeys);
             const txn = await this._storage.readWriteTxn([
                 this._storage.storeNames.deviceIdentities,