Unable to decrypt messages for previous messages in my rooms

[patriknorlander]

Steps to reproduce

When logging in I was asked to verifiy with other device or with passphrase. Entered passphrase. Get unable to decrypt messages in all my chats.

Outcome

What did you expect?

What happened instead?

Operating system

WIndows 11

Browser information

Edge: Version 128.0.2739.67

URL for webapp

app.element.io

Application version

Element-version: 1.11.79 Kryptoversion: Rust SDK 0.7.2 (7a21514), Vodozemac 0.7.0

Homeserver

matrix.org

Will you send logs?

Yes

[danielcb]

We've also got this problem. 6 users in sum. Migrated from synapse/element-web to synapse/matrix-authentication-service/element-web.

All users need to re-verify, which all users did. Everything works for 5 of the users. One user sees only 'Unable to decrypt message' for all previous messages, although the verification succeeded and all his sessions are shown as verified.

[richvdh]

We investigated the problem for the original reporter.

In short, key backup was not signed by the user's keys. Most likely, that happened because key backup had been reset from a device which was not verified and therefore did not have the cross-signing keys, so could not sign the backup.

Unfortunately, that happened some time ago, so we lack client-side and server-side logs as to how that could have taken place (or even which platform the relevant device was on).

@danielcb if you are still having problems, please open a new issue, and send debug logs from within the affected client(s).

[richvdh]

Opened element-hq/element-meta#2595 to keep track of the root cause here