Sending/receiving messages with a new device resulting in **Unable to Decrypt**

[ihodes]

Some clients in the rooms work/the key exchange clearly took place, but some did not.

I keep getting ** Unable to decrypt: The sender's device has not sent us the keys for this message**, and they see it for my messages as well.

Any ideas on what we can do?

[manuroe]

The feature is still in beta. We are fixing edge cases that make such issue happen in our Matrix clients. See element-hq/element-web#2996 for the known use cases bugs we are chasing.

[manuroe]

Most of UISI (Unknown Inbound Session Id) issues must have been fixed in matrix-ios-sdk v0.7.8.
Riot-iOS will embed all fixes in the coming v0.3.10 release.

From Riot v0.3.10, if people still gets UISIs for your messages, you can "Clear Cache" from the app settings.
This action will force the download of missing devices keys. Your next messages should be then correctly encrypted for all recipients devices.

[ihodes]

Thanks for addressing!

[jimmycuadra]

Clearing the cache on the newest version of Riot (Electron on macOS) did not fix this for me. I'm still seeing:

** Unable to decrypt: The sender's device has not sent us the keys for this message. **

in rooms where encryption was previously working.

matrix-react-sdk version: 0.8.7
riot-web version: 0.9.8
olm version: 2.2.1

[manuroe]

@jimmycuadra: Riot (Electron on macOS) is based on riot-web, which is written in js.
I do not think that the clear cache button on riot-web does the same trick as Android and iOS to reset devices keys.

[jimmycuadra]

Oh sorry, I didn't notice this was an iOS issue. I think someone linked me to it a while back when I asked about the error message and I subscribed without noticing that. Is there a riot-web issue for the same error message?

[manuroe]

There is element-hq/element-web#2996 that compiles all issues related to this.