diff --git a/crates/matrix-sdk/CHANGELOG.md b/crates/matrix-sdk/CHANGELOG.md
index be5a51a8e..703be0e1f 100644
--- a/crates/matrix-sdk/CHANGELOG.md
+++ b/crates/matrix-sdk/CHANGELOG.md
@@ -8,6 +8,9 @@ All notable changes to this project will be documented in this file.
 
 ### Features
 
+- [**breaking**] `matrix_sdk::error::Error` has a new variant `Timeout` which occurs when
+  a cross-signing reset does not succeed after some period of time.
+  ([#6325](https://github.com/matrix-org/matrix-rust-sdk/pull/6325))
 - The `beacon_info` start event ([MSC3672](https://github.com/matrix-org/matrix-spec-proposals/pull/3672))
   is now included when computing the latest event for a room, so live location sharing
   sessions can be surfaced as a room's most recent activity.
diff --git a/crates/matrix-sdk/src/encryption/mod.rs b/crates/matrix-sdk/src/encryption/mod.rs
index bfe143511..98cdce7a4 100644
--- a/crates/matrix-sdk/src/encryption/mod.rs
+++ b/crates/matrix-sdk/src/encryption/mod.rs
@@ -25,6 +25,7 @@ use std::{
     path::PathBuf,
     str::FromStr,
     sync::Arc,
+    time::Duration,
 };
 
 use eyeball::{SharedObservable, Subscriber};
@@ -48,6 +49,7 @@ use matrix_sdk_base::{
             },
         },
     },
+    sleep::sleep,
 };
 use matrix_sdk_common::{executor::spawn, locks::Mutex as StdMutex};
 use ruma::{
@@ -298,27 +300,50 @@ impl CrossSigningResetHandle {
     /// authentication to be done on the side of the OAuth 2.0 server or by
     /// providing additional [`AuthData`] the homeserver requires.
     pub async fn auth(&self, auth: Option<AuthData>) -> Result<()> {
-        let mut upload_request = self.upload_request.clone();
-        upload_request.auth = auth;
+        // Poll to see whether the reset has been authorized twice per second.
+        const RETRY_EVERY: Duration = Duration::from_millis(500);
 
-        while let Err(e) = self.client.send(upload_request.clone()).await {
-            if *self.is_cancelled.lock().await {
-                return Ok(());
-            }
+        // Give up after two minutes of polling.
+        const TIMEOUT: Duration = Duration::from_mins(2);
 
-            match e.as_uiaa_response() {
-                Some(uiaa_info) => {
-                    if uiaa_info.auth_error.is_some() {
-                        return Err(e.into());
-                    }
+        tokio::time::timeout(TIMEOUT, async {
+            let mut upload_request = self.upload_request.clone();
+            upload_request.auth = auth;
+
+            debug!(
+                "Repeatedly PUTting to keys/device_signing/upload until it works \
+                or we hit a permanent failure."
+            );
+            while let Err(e) = self.client.send(upload_request.clone()).await {
+                if *self.is_cancelled.lock().await {
+                    return Ok(());
                 }
-                None => return Err(e.into()),
+
+                match e.as_uiaa_response() {
+                    Some(uiaa_info) => {
+                        if uiaa_info.auth_error.is_some() {
+                            return Err(e.into());
+                        }
+                    }
+                    None => return Err(e.into()),
+                }
+
+                debug!(
+                    "PUT to keys/device_signing/upload failed with 401. Retrying after \
+                    a short delay."
+                );
+                sleep(RETRY_EVERY).await;
             }
-        }
 
-        self.client.send(self.signatures_request.clone()).await?;
+            self.client.send(self.signatures_request.clone()).await?;
 
-        Ok(())
+            Ok(())
+        })
+        .await
+        .unwrap_or_else(|_| {
+            warn!("Timed out waiting for keys/device_signing/upload to succeed.");
+            Err(Error::Timeout)
+        })
     }
 
     /// Cancel the ongoing identity reset process
diff --git a/crates/matrix-sdk/src/error.rs b/crates/matrix-sdk/src/error.rs
index 582380616..6ea097f50 100644
--- a/crates/matrix-sdk/src/error.rs
+++ b/crates/matrix-sdk/src/error.rs
@@ -417,6 +417,10 @@ pub enum Error {
     /// An error happened while attempting to change power levels.
     #[error("power levels error: {0}")]
     PowerLevels(#[from] PowerLevelsError),
+
+    /// We timed out attempting to complete an operation.
+    #[error("timed out")]
+    Timeout,
 }
 
 #[rustfmt::skip] // stop rustfmt breaking the `<code>` in docs across multiple lines