diff --git a/packages/sync-server/src/app.ts b/packages/sync-server/src/app.ts
index d1dbc4d041..079fb2058a 100644
--- a/packages/sync-server/src/app.ts
+++ b/packages/sync-server/src/app.ts
@@ -177,7 +177,6 @@ export async function run() {
   const openIdConfig = config?.getProperties()?.openId;
   if (
     openIdConfig?.discoveryURL ||
-    // @ts-expect-error FIXME no types for config yet
     openIdConfig?.issuer?.authorization_endpoint
   ) {
     console.log('OpenID configuration found. Preparing server to use it');
diff --git a/packages/sync-server/src/load-config.js b/packages/sync-server/src/load-config.js
index 43794ad52f..82183ce310 100644
--- a/packages/sync-server/src/load-config.js
+++ b/packages/sync-server/src/load-config.js
@@ -205,8 +205,7 @@ const configSchema = convict({
     },
     issuer: {
       doc: 'OpenID issuer',
-      format: Object,
-      default: {},
+
       name: {
         doc: 'Name of the provider',
         default: '',
diff --git a/packages/sync-server/src/load-config.test.js b/packages/sync-server/src/load-config.test.js
index 0c85d84ac1..26e9c35440 100644
--- a/packages/sync-server/src/load-config.test.js
+++ b/packages/sync-server/src/load-config.test.js
@@ -110,3 +110,32 @@ describe('tokenExpiration format', () => {
     );
   });
 });
+
+describe('config schema', () => {
+  it('should parse nested object from environment variables correctly', () => {
+    const authorizationEndpoint =
+      'https://testprovider.com/.well-known/openid-configuration';
+    process.env.TEST_OPENID_AUTHORIZATION_ENDPOINT = authorizationEndpoint;
+
+    const testSchema = convict({
+      openId: {
+        doc: 'OpenID authentication settings.',
+
+        issuer: {
+          doc: 'OpenID issuer',
+
+          authorization_endpoint: {
+            doc: 'Authorization endpoint',
+            default: '',
+            format: String,
+            env: 'TEST_OPENID_AUTHORIZATION_ENDPOINT',
+          },
+        },
+      },
+    });
+    expect(() => testSchema.validate()).not.toThrow();
+    expect(testSchema.get('openId.issuer.authorization_endpoint')).toBe(
+      authorizationEndpoint,
+    );
+  });
+});
diff --git a/upcoming-release-notes/6061.md b/upcoming-release-notes/6061.md
new file mode 100644
index 0000000000..0a1f600a5a
--- /dev/null
+++ b/upcoming-release-notes/6061.md
@@ -0,0 +1,6 @@
+---
+category: Bugfix
+authors: [lwschan]
+---
+
+fix: openId.issuer config not loading from env vars