diff --git a/client/src/crypto/groupCrypto.ts b/client/src/crypto/groupCrypto.ts
index a7cfd85..d4726cc 100644
--- a/client/src/crypto/groupCrypto.ts
+++ b/client/src/crypto/groupCrypto.ts
@@ -178,10 +178,20 @@ export async function distributeSenderKey(
   recipientIkPub: string,
   recipientKemPub: string | null | undefined
 ): Promise<{ encrypted_key: string; header: string }> {
-  const result = await encryptHybrid(recipientIkPub, recipientKemPub, senderKey)
-  return {
-    encrypted_key: result.ciphertext,
-    header: result.header,
+  try {
+    const result = await encryptHybrid(recipientIkPub, recipientKemPub, senderKey)
+    return {
+      encrypted_key: result.ciphertext,
+      header: result.header,
+    }
+  } catch (err) {
+    console.error('[groupCrypto] distributeSenderKey failed:', {
+      recipientIkPubLen: recipientIkPub?.length,
+      kemPubPresent: !!recipientKemPub,
+      senderKeyLen: senderKey?.length,
+      error: err,
+    })
+    throw err
   }
 }
 
@@ -201,5 +211,17 @@ export async function receiveSenderKey(
   myPrivKey: string,
   myKemPriv: string | null | undefined
 ): Promise<string> {
-  return await decryptHybrid(header, myPrivKey, myKemPriv, encryptedKey)
+  try {
+    const result = await decryptHybrid(header, myPrivKey, myKemPriv, encryptedKey)
+    return result
+  } catch (err) {
+    console.error('[groupCrypto] receiveSenderKey decryption failed:', {
+      encryptedKeyLen: encryptedKey?.length,
+      headerLen: header?.length,
+      myPrivKeyLen: myPrivKey?.length,
+      kemPrivPresent: !!myKemPriv,
+      error: err,
+    })
+    throw err
+  }
 }
diff --git a/client/src/hooks/useSocket.ts b/client/src/hooks/useSocket.ts
index 4700526..0a693c1 100644
--- a/client/src/hooks/useSocket.ts
+++ b/client/src/hooks/useSocket.ts
@@ -125,12 +125,22 @@ export function useSocket() {
                 await fetchAndStoreSenderKeys(data.group_id)
                 sk = getSenderKey(data.group_id, data.from)
               }
+              if (!sk) {
+                // Still no key — retry after a brief delay.
+                // The sender distributes keys via HTTP POST before sending the WS message,
+                // but there can be a race where the message arrives before the POST response
+                // has been fully committed to the DB.
+                console.log(`[useSocket] Retrying sender key fetch after 1s delay for ${data.from} in group ${data.group_id}...`)
+                await new Promise(r => setTimeout(r, 1000))
+                await fetchAndStoreSenderKeys(data.group_id)
+                sk = getSenderKey(data.group_id, data.from)
+              }
               if (sk) {
                 const text = await decryptWithSenderKey(data.ciphertext, data.nonce, sk.senderKey)
                 msgToAdd = { ...data, decrypted: text }
               } else {
                 // Still don't have sender key — store as 🔒 but keep nonce in data for retry
-                console.warn(`[useSocket] Still no sender key for ${data.from} in group ${data.group_id} after fetch. Message will show 🔒`)
+                console.warn(`[useSocket] Still no sender key for ${data.from} in group ${data.group_id} after retries. Message will show 🔒`)
                 msgToAdd = { ...data, decrypted: '🔒' }
               }
             } catch (err) {
@@ -218,11 +228,15 @@ export function useSocket() {
       if (pending && data.msg_id) {
         const chatId = pending.group_id || pending.to
         if (chatId) {
-          useStore.getState().addMessage(chatId, {
+          // Build the message to add. For encrypted group messages, pendingMsg
+          // now carries encryption metadata (ciphertext, nonce, sender_key_version)
+          // set during the encryption step in Chat.tsx.
+          const msgToStore: any = {
             ...pending,
             id: data.msg_id,
             ts: data.ts || Date.now(),
-          })
+          }
+          useStore.getState().addMessage(chatId, msgToStore)
         }
         ;(window as any).__pendingMsg = null
       }
diff --git a/client/src/pages/Chat.tsx b/client/src/pages/Chat.tsx
index d526982..c15ca65 100644
--- a/client/src/pages/Chat.tsx
+++ b/client/src/pages/Chat.tsx
@@ -573,13 +573,20 @@ export default function Chat() {
                         const memberKeys = await get(`/api/users/${m.id}`)
                         ikPub = memberKeys?.ik_pub
                         kemPub = memberKeys?.kem_pub
-                      } catch {}
+                      } catch (fetchKeyErr) {
+                        console.warn(`[Chat] Failed to fetch public keys for member ${m.id}:`, fetchKeyErr)
+                      }
                     }
                     if (ikPub && keys) {
                       try {
-                        const dist = await distributeSenderKey(newKey, ikPub, kemPub)
+                        // Pass null for kemPub — kem_pub on server is an Ed25519 signing key,
+                        // NOT a valid Kyber KEM key. Passing it causes unnecessary Kyber encap
+                        // failures. Using null goes directly to pure ECDH (version 1).
+                        const dist = await distributeSenderKey(newKey, ikPub, null)
                         distributions.push({ to_id: m.id, encrypted_key: dist.encrypted_key, header: dist.header })
-                      } catch {}
+                      } catch (distMemberErr) {
+                        console.warn(`[Chat] distributeSenderKey failed for member ${m.id}:`, distMemberErr)
+                      }
                     }
                   }
                   if (distributions.length > 0) {
@@ -602,6 +609,12 @@ export default function Chat() {
             }
             if (sk && !sent) {
               const encrypted = await encryptWithSenderKey(content, sk.senderKey)
+              // Update pendingMsg with actual encryption metadata so the ack handler
+              // stores the message with correct encrypted fields (matching server data).
+              // This ensures consistency when messages are later loaded from server.
+              pendingMsg.ciphertext = encrypted.ciphertext
+              pendingMsg.nonce = encrypted.nonce
+              pendingMsg.sender_key_version = sk.keyVersion
               sent = sendWs({ type: 'message', msg_type: msgType, group_id: id, ciphertext: encrypted.ciphertext, nonce: encrypted.nonce, sender_key_version: sk.keyVersion })
             }
           } catch (encErr) {