docs(common): Use exact license error messages and add error codes (#2878)

* Use correct license key errors and codes

* Polish error messages

* Polish FAQ

* Update ci-cd-license-key.md

* Update troubleshooting/license-key-errors.md

Author: dimodi

deployment/ci-cd-license-key.md

@@ -63,7 +63,7 @@ steps:
 ### Use TELERIK_LICENSE_PATH
 
 1. [Add a secure file](https://learn.microsoft.com/en-us/azure/devops/pipelines/library/secure-files) and grant any necessary permissions to use it in the pipeline.
-1. [Download the secure file](https://learn.microsoft.com/en-us/azure/devops/pipelines/tasks/reference/download-secure-file-v1?view=azure-pipelines) during pipeline run. The secure file path is available through the [`secureFilePath` output](https://learn.microsoft.com/en-us/azure/devops/pipelines/tasks/reference/download-secure-file-v1?view=azure-pipelines#output-variables).
+1. [Download the secure file](https://learn.microsoft.com/en-us/azure/devops/pipelines/tasks/reference/download-secure-file-v1?view=azure-pipelines) in a task with a `name`. The secure file path is available to other tasks through the [`secureFilePath` output](https://learn.microsoft.com/en-us/azure/devops/pipelines/tasks/reference/download-secure-file-v1?view=azure-pipelines#output-variables).
 1. Set the `TELERIK_LICENSE_PATH` environment variable in all tasks, steps, or scripts that build and publish the Blazor app.
 
 >caption Using a TELERIK_LICENSE_PATH environment variable in Azure Pipeline YAML

installation/license-key.md

@@ -63,7 +63,7 @@ The new license key includes information about all previous purchases. This proc
 
 ## Frequently Asked Questions
 
-#### Does the license key expire?
+### Does the license key expire?
 
 Yes, the license key expires at the end of your subscription:
 
@@ -79,7 +79,7 @@ You need to download and install a new license key after:
 
 An expired [perpetual license](https://www.telerik.com/purchase/faq/licensing-purchasing#licensing) key is valid for all Telerik UI for Blazor versions published before the license expiration date.
 
-#### Will Telerik UI for Blazor function with an expired license key?
+### Will Telerik UI for Blazor work with an expired license key?
 
 This depends on the [Telerik UI for Blazor license type (perpetual, subscription, or trial)](https://www.telerik.com/purchase/faq/licensing-purchasing#licensing):
 
@@ -93,44 +93,45 @@ Scenarios that do not match the above three descriptions result in the following
 * A watermark appears on Telerik UI for Blazor components.
 * [A warning message appears in the application's build log](slug:troubleshooting-license-key-errors).
 
-#### I updated the Telerik UI for Blazor version in my project and license errors appeared. Why?
+### I updated Telerik UI for Blazor in my app and got license errors. Why?
 
 The most likely cause is that the new Telerik UI for Blazor version was released after the expiration date of your current license or license key. To fix this issue:
 
 1. Renew your Telerik UI for Blazor license if necessary.
 1. [Update your license key](slug:installation-license-key)
 
-#### Can I use the same license key in multiple builds?
+### Can I use the same license key in multiple builds?
 
 You can use one license key in multiple pipelines, builds, and environments. However, each individual developer must use their own unique personal license key in their development environment.
 
-#### Do I need an Internet connection to activate the license?
+### Do I need Internet to activate the license?
 
 No, the license validation and activation occur offline.
 
-#### Do I have to add the license key to source control?
+### Should I add the license key to source control?
 
 No, do not add the `telerik-license.txt` license key file or its contents to source control.
 
 Do not store the license key in plain text in GitHub Actions Workflow definitions. Build servers [must use the `TELERIK_LICENSE` environment variable](slug:deployment-license-key).
 
-#### What happens if both the environment variable and the license key file are present?
+### What happens if I use both the environment variable and the license key file?
 
 If both the `TELERIK_LICENSE` environment variable and the `telerik-license.txt` file are present, then the environment variable will be used.
 To use the license key file, unset the environment variable.
 
-#### What happens if several license key files exist?
+### What happens if several license key files exist?
 
 If both a global and a project-specific `telerik-license.txt` files exist, then the project-specific license key will be used.
 
-#### My team has more than one license holder. Which key do we have to use?
+### My team has multiple licenses. Which key should we use?
 
 To activate Telerik UI for Blazor:
 
 * [Every developer must be assigned their own license or seat](https://www.telerik.com/purchase/faq/licensing-purchasing).
 * Every developer must use a license key that is associated with their personal Telerik account.
+* You can use any of the available [license keys in cloud build CI/CD environments](slug:deployment-license-key).
 
-#### Are earlier Telerik UI for Blazor versions affected?
+### Are earlier Telerik UI for Blazor versions affected?
 
 No, versions up to **7.1.0** released prior to February 2025 do not require a license key.
 

troubleshooting/license-key-errors.md

@@ -18,51 +18,57 @@ This page provides solutions for license key errors that you may encounter while
 
 A Telerik license key error may occur in the following scenarios:
 
-* Missing license key.
-* Using an expired subscription license after the end of the subscription term.
-* Using a perpetual license with a product version that was released outside the validity period of your license.
-* Using an expired trial license.
-* Using an outdated license key after making renewals or purchases.
-* Using a license key that doesn't include Telerik UI for Blazor.
-* Using conflicting license keys in the same environment. For example, using one global license key and one in the app. Or, using a license key file together with an environment variable in CI/CD environment.
+* The license key is missing or not set up correctly.
+* The license key is outdated or does not include the product version that you are using.
+* Your subscription license or trial has expired.
+* You have different conflicting license keys in the same environment. For example, using one global license key and one in the app. Or, using a license key file together with an environment variable in CI/CD environment.
 
-Refer to the error messages below for specific tips.
+Refer to the specific error messages and tips below.
 
 ## Error Messages
 
-* [No license key is detected](#no-license-key-is-detected)
-* [Invalid license key](#invalid-license-key)
-* [Your subscription license has expired](#your-subscription-license-has-expired)
-* [Your perpetual license is invalid](#your-perpetual-license-is-invalid)
-* [Your trial license has expired](#your-trial-license-has-expired)
-* [Your license is not valid for the detected product(s)](#your-license-is-not-valid-for-the-detected-products)
+### No Telerik or Kendo UI product references detected in project (TKL001)
 
-### No license key is detected
+This error can occur when a project references `Telerik.Licensing`, but not any other Telerik packages. In this case, remove the `Telerik.Licensing` package from the project. If your scenario is different, [contact Technical Support](https://www.telerik.com/account/support-center).
 
-[Install a license key file](slug:installation-license-key). If you already downloaded it, make sure it's [saved at the right place](slug:installation-license-key#manual-installation).
+### No Telerik and Kendo UI License file found (TKL002)
 
-### Invalid license key
+The error means that the license key is missing or not set up corrently. For example, the environment variable is not set or [the license file may be at the wrong place](slug:installation-license-key#manual-installation).
 
-Follow the [automatic](slug:installation-license-key#automatic-installation) or [manual](slug:installation-license-key#manual-installation) installation steps from scratch.
+[Install a license key](slug:installation-license-key) again. Also check how to [set up a license key in CI/CD environments](slug:deployment-license-key).
 
-### Your subscription license has expired
+### Corrupted Telerik and Kendo UI License Key content (TKL003)
 
-<a href="https://www.telerik.com/account/your-licenses" target="_blank">Renew your subscribtion</a>. Then, [update your license key](slug:installation-license-key#license-key-updates).
+The license key is detected, but its value is invalid and cannot be decrypted. For example, if you have set a `TELERIK_LICENSE` environment variable through the Windows operating system's UI, then it may be truncated. In such cases, remove the environment variable and use a license key file instead.
 
-### Your perpetual license is invalid
+Follow the [automatic](slug:installation-license-key#automatic-installation) or [manual](slug:installation-license-key#manual-installation) installation steps from scratch. Also check how to [set up a license key in CI/CD environments](slug:deployment-license-key).
 
-You are using a product version released outside the validity period of your perpetual license. To remove the error message, do either of the following:
+### Unable to locate licenses for all products (TKL004)
 
-* <a href="https://www.telerik.com/account/your-licenses" target="_blank">Renew your subscribtion</a>. Then, [update your license key](slug:installation-license-key#license-key-updates).
-* Downgrade your app to a Telerik UI for Blazor version that was released within the subscription period of your perpetual license.
+Your license is not valid for the detected product(s), because it doesn't include them.
 
-### Your trial license has expired
+[Review the purchase options for Telerik UI for Blazor](https://www.telerik.com/purchase/blazor-ui). If you have already purchased the required license, then, [update your license key](slug:installation-license-key#license-key-updates).
 
-<a href="https://www.telerik.com/purchase/blazor-ui" target="_blank">Purchase a commercial license to continue using Telerik UI for Blazor</a>.
+### Telerik UI for Blazor is not listed in your current license file (TKL101)
 
-### Your license is not valid for the detected product(s)
+Your license key does not include Telerik UI for Blazor.
 
-<a href="https://www.telerik.com/purchase/blazor-ui" target="_blank">Review the purchase options for Telerik UI for Blazor</a>. Then, [update your license key](slug:installation-license-key#license-key-updates).
+[Review the purchase options for Telerik UI for Blazor](https://www.telerik.com/purchase/blazor-ui). If you have already purchased the required license, then, [update your license key](slug:installation-license-key#license-key-updates).
+
+### Your current license has expired (TKL102)
+
+This error applies to perpetual licenses. It means that you are using a product version released outside the validity period of your license. To remove the error message, do either of the following:
+
+* [Renew your license](https://www.telerik.com/account/your-licenses) and then, [update your license key](slug:installation-license-key#license-key-updates).
+* Use a Telerik UI for Blazor version that was released within the subscription period of your perpetual license.
+
+### Your subscription has expired (TKL103, TKL104)
+
+This error applies to subscription licenses. [Renew your subscription](https://www.telerik.com/account/your-licenses) and then, [update your license key](slug:installation-license-key#license-key-updates).
+
+### Your trial expired (TKL105)
+
+[Purchase a commercial license to continue using Telerik UI for Blazor](https://www.telerik.com/purchase/blazor-ui).
 
 ## See Also