diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index a9cc7ee4..9ec6850c 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1399,6 +1399,9 @@ importers:
       p-map:
         specifier: ^4.0.0
         version: 4.0.0
+      promise-retry:
+        specifier: ^2.0.1
+        version: 2.0.1
       qs:
         specifier: ^6.10.3
         version: 6.11.0
@@ -1487,6 +1490,9 @@ importers:
       '@types/oidc-provider':
         specifier: ^7.8.1
         version: 7.11.1
+      '@types/promise-retry':
+        specifier: ^1.1.3
+        version: 1.1.3
       '@types/send':
         specifier: ^0.17.1
         version: 0.17.1
@@ -12938,6 +12944,12 @@ packages:
     resolution: {integrity: sha512-ZTaqn/qSqUuAq1YwvOFQfVW1AR/oQJlLSZVustdjwI+GZ8kr0MSHBj0tsXPW1EqHubx50gtBEjbPGsdZwQwCjQ==}
     dev: false
 
+  /@types/promise-retry@1.1.3:
+    resolution: {integrity: sha512-LxIlEpEX6frE3co3vCO2EUJfHIta1IOmhDlcAsR4GMMv9hev1iTI9VwberVGkePJAuLZs5rMucrV8CziCfuJMw==}
+    dependencies:
+      '@types/retry': 0.12.0
+    dev: true
+
   /@types/prop-types@15.7.5:
     resolution: {integrity: sha512-JCB8C6SnDoQf0cNycqd/35A7MjcnK+ZTqE7judS6o7utxUCg6imJg3QK2qzHKszlTjcj2cn+NwMB2i96ubpj7w==}
 
@@ -18450,6 +18462,10 @@ packages:
     resolution: {integrity: sha512-Ds/TEoZjwggRoz/Q2O7SE3i4Jm66mqTDfmdHdq/7DKVk3bro9Q8h6WdXKdPqFLMoqxrDK5SVRzHVPOS6uuGtrg==}
     dev: true
 
+  /err-code@2.0.3:
+    resolution: {integrity: sha512-2bmlRpNKBxT/CRmPOlyISQpNj+qSeYvcym/uT0Jx2bMOlKLtSy1ZmLuVxSEKKyor/N5yhvp/ZiG1oE3DEYMSFA==}
+    dev: false
+
   /errno@0.1.8:
     resolution: {integrity: sha512-dJ6oBr5SQ1VSd9qkk7ByRgb/1SH4JZjCHSW/mr63/QcXO9zLVxvJ6Oy13nio03rxpSnVDDjFor75SjVeZWPW/A==}
     hasBin: true
@@ -28303,6 +28319,14 @@ packages:
         optional: true
     dev: true
 
+  /promise-retry@2.0.1:
+    resolution: {integrity: sha512-y+WKFlBR8BGXnsNlIHFGPZmyDf3DFMoLhaflAnyZgV6rG6xu+JwesTo2Q9R6XwYmtmwAFCkAk3e35jEdoeh/3g==}
+    engines: {node: '>=10'}
+    dependencies:
+      err-code: 2.0.3
+      retry: 0.12.0
+    dev: false
+
   /promise.allsettled@1.0.5:
     resolution: {integrity: sha512-tVDqeZPoBC0SlzJHzWGZ2NKAguVq2oiYj7gbggbiTvH2itHohijTp7njOUA0aQ/nl+0lr/r6egmhoYu63UZ/pQ==}
     engines: {node: '>= 0.4'}
@@ -31100,6 +31124,11 @@ packages:
     engines: {node: '>=0.12'}
     dev: true
 
+  /retry@0.12.0:
+    resolution: {integrity: sha512-9LkiTwjUh6rT555DtE9rTX+BKByPfrMzEAtnlEtdEwr3Nkffwiihqe2bWADg+OQRjt9gl6ICdmB/ZFDCGAtSow==}
+    engines: {node: '>= 4'}
+    dev: false
+
   /retry@0.13.1:
     resolution: {integrity: sha512-XQBQ3I8W1Cge0Seh+6gjj03LbmRFWuoszgK9ooCpwYIrhhoO80pfq4cUkU5DkknwfOfFteRwlZ56PYOGYyFWdg==}
     engines: {node: '>= 4'}
diff --git a/server/models/group/invite.ts b/server/models/group/invite.ts
index 4e081268..5c7cd295 100644
--- a/server/models/group/invite.ts
+++ b/server/models/group/invite.ts
@@ -11,6 +11,7 @@ import type { Types } from 'mongoose';
 import { nanoid } from 'nanoid';
 import { User } from '../user/user';
 import { Group } from './group';
+import promiseRetry from 'promise-retry';
 
 function generateCode() {
   return nanoid(8);
@@ -73,9 +74,27 @@ export class GroupInvite extends TimeStamps implements Base {
       expiredAt = undefined;
     }
 
+    const code = await promiseRetry(
+      async () => {
+        const code = generateCode();
+        const exists = await this.exists({ code });
+
+        if (exists) {
+          throw new Error('Cannot find unused invite code, please try again.');
+        }
+
+        return code;
+      },
+      {
+        minTimeout: 0,
+        maxTimeout: 0,
+        retries: 5,
+      }
+    );
+
     const invite = await this.create({
       groupId,
-      code: generateCode(),
+      code,
       creator,
       expiredAt,
     });
diff --git a/server/package.json b/server/package.json
index afb83ce9..57e564c5 100644
--- a/server/package.json
+++ b/server/package.json
@@ -67,6 +67,7 @@
     "nodemailer": "^6.7.2",
     "oidc-provider": "^7.10.6",
     "p-map": "^4.0.0",
+    "promise-retry": "^2.0.1",
     "qs": "^6.10.3",
     "redlock": "^4.2.0",
     "send": "^0.18.0",
@@ -98,6 +99,7 @@
     "@types/node": "16.11.7",
     "@types/nodemailer": "^6.4.4",
     "@types/oidc-provider": "^7.8.1",
+    "@types/promise-retry": "^1.1.3",
     "@types/send": "^0.17.1",
     "@types/serve-static": "^1.15.0",
     "@types/swagger-jsdoc": "^6.0.1",