diff --git a/server/src/routes/sse.js b/server/src/routes/sse.js
index e8b32dd..d96e125 100644
--- a/server/src/routes/sse.js
+++ b/server/src/routes/sse.js
@@ -104,22 +104,37 @@ export async function registerSseRoutes(fastify) {
       'X-Accel-Buffering': 'no',
     })
 
+    let closed = false
+
+    function safeWrite(chunk) {
+      if (closed) return
+      try {
+        reply.raw.write(chunk)
+      } catch {
+        closed = true
+        cleanUp()
+      }
+    }
+
     const userId = request.user.sub
     const admin = isAdminUser(request.user)
 
-    reply.raw.write(formatHeartbit())
+    safeWrite(formatHeartbit())
 
     const heartbitTimer = setInterval(() => {
-      reply.raw.write(formatHeartbit())
+      safeWrite(formatHeartbit())
     }, 30_000)
 
-    const cleanup = buildSseListeners(userId, admin, fastify.eventBus, (chunk) => {
-      reply.raw.write(chunk)
-    })
+    const removeListeners = buildSseListeners(userId, admin, fastify.eventBus, safeWrite)
 
-    request.raw.on('close', () => {
+    function cleanUp() {
+      if (closed) return
+      closed = true
       clearInterval(heartbitTimer)
-      cleanup()
-    })
+      removeListeners()
+    }
+
+    request.raw.on('close', cleanUp)
+    request.raw.on('error', cleanUp)
   })
 }