diff --git a/doc/subscriptions/subscription-add-ons.md b/doc/subscriptions/subscription-add-ons.md
index e22e7e7b8fdd353148a3727a538ed6c6b21d5b3b..f68feaeb69a98c1525ba0e9059f7f2134b7092aa 100644
--- a/doc/subscriptions/subscription-add-ons.md
+++ b/doc/subscriptions/subscription-add-ons.md
@@ -97,7 +97,7 @@ Prerequisites:
 
 - You must purchase the GitLab Duo Pro or GitLab Duo Enterprise add-on.
 
-### For GitLab.com
+### For GitLab.com and GitLab Dedicated
 
 Prerequisites:
 
@@ -185,7 +185,7 @@ You can assign or remove seats in bulk for multiple users.
 
 GitLab.com groups can use SAML Group Sync to [manage GitLab Duo seat assignments](../user/group/saml_sso/group_sync.md#manage-gitlab-duo-seat-assignment).
 
-### For GitLab.com
+### For GitLab.com and GitLab Dedicated
 
 1. On the left sidebar, select **Search or go to** and find your group.
 1. Select **Settings > GitLab Duo**.
@@ -333,3 +333,85 @@ On the **Usage quotas** page, if you experience both of the following, you will
   ```
 
 As a workaround, you can use the GraphQL queries in [this snippet](https://gitlab.com/gitlab-org/gitlab/-/snippets/3763094) to assign seats to users.
+
+# GitLab Duo Core Troubleshooting Guide for Dedicated Instances
+
+
+- Duo Core should work out-of-the-box on GitLab 18.3+ for Premium/Ultimate customers
+- Pre-production Dedicated instances do NOT support Duo Core by design
+
+# Common Issues & Solutions
+
+### Issue 1: "Duo Core settings missing from Admin panel"
+Symptoms:
+
+- No "GitLab Duo" section in Admin area
+- Missing Duo configuration options
+- API call shows "addOnPurchases": []
+- WebIDE timeout message: `Activating extension GitLab.gitlab-workflow failed`
+- Missing Admin settings in panel
+- Note: The timeout message alone may not indicate this specific issue
+
+
+Root Cause: License may not be properly synchronized
+
+Resolution Steps:
+
+- Create a support ticket to verify if the license is properly synchronized with instance. Support may have to check if the license is properly synchronized. See [internal issue](https://gitlab.com/gitlab-com/request-for-help/-/issues/3369#note_2729514486)
+
+- If license is outdated, request new license generation
+
+### Issue 2: "Web IDE shows GitLab Language Server failed to start"
+Symptoms:
+
+- Error: "GitLab-workflow failed: the GitLab Language server failed to start in 10 seconds"
+- Duo Chat not responding in Web IDE
+- Console errors about "Platform is missing!"
+
+Root Cause: Network connectivity issues to cloud.gitlab.com and customers.gitlab.com. Check Firewall/allowlist blocking outbound connections
+
+Resolution Steps:
+
+* Customer administrator should follow https://docs.gitlab.com/security/webhooks/#gitlab-duo-functionality-is-blocked to troubleshoot.
+
+Test connectivity from the Dedicated instance
+
+### Issue 3: "GitLab Duo Chat in VS Code Remote SSH or WSL sessions timeouts"
+
+Symptoms: `Error: Webview didn't initialize in 10000ms.`
+
+### Impacted Offerings:
+- GitLab.com
+- GitLab Dedicated
+- GitLab Self-Managed
+
+### Impacted versions
+- GitLab VS Code Extension: 6.8.0 and later
+
+### Cause
+
+The webview initialization timeout is hardcoded to 10 seconds in `duo_chat_controller.ts`. Remote environments introduce additional latency that exceeds this timeout period. The extension may also attempt to incorrectly connect to a 127.0.0.1 address. See KB article [Gitlab Duo Chat fails to initialize in remote enviroments](https://support.gitlab.com/hc/en-us/articles/20475947055132-GitLab-Duo-Chat-fails-to-initialize-in-remote-environments).
+
+### Resolution
+
+In VS Code, on the top bar, go to **Code > Settings > Settings**.
+
+1. On the top right corner, select Open **Settings (JSON)** to edit your settings.json file.
+Alternatively, press F1, enter **Preferences: Open Settings (JSON)**, and select it.
+2. Add or modify this setting:
+`"gitlab.featureFlags.languageServerWebviews": false`
+3. Save your changes and reload VS Code.
+
+### Issue 4 Web IDE not loading due to CORS
+
+Symptoms: `Unable to resolve resource`
+
+## Troubleshooting
+- Check Har file for logs. See doc [Create HAR](https://docs.gitlab.com/user/application_security/api_fuzzing/create_har_files/) files.
+- Look for CORS errors `failed to load because it violates the following Content Security policy`
+
+## Resolution
+
+- Update to GitLab Workflow Extension version 6.35.1 or later
+- add `https://*.cdn.web-ide.gitlab-static.net` to the CORS policy
+- See doc on Duo [CORS issues](https://docs.gitlab.com/user/project/web_ide/#cors-issues)