26 Troubleshooting and FAQs

These topics cover some common issues and how to address them.

Resolving the error “Page cannot be previewed”

If you're having trouble seeing the preview of your app extension page in the Page Designer, you might need to check your browser settings to make sure that the browser isn't blocking your VB Studio instance from accessing your Oracle Cloud Application instance. This can happen when the instances are not in the same host domain and your Chrome browser's settings are set to the default.

You might see something like this in the Page Designer instead of seeing the app extension page:

Description of the illustration trouble-no-preview.png

To resolve this page preview error, you'll need to edit some of your Chrome browser settings.

1. Note the host domain of your Oracle Cloud Application instance.
   For example, if the URL of your Oracle Cloud Application is something like os1.mysubdomain.OC_HOST_URL.com, the host domain is OC_HOST_URL.com.
2. Open the browser's Cookies settings page (chrome://settings/cookies) and disable Block third-party cookies, if it's not already disabled.

   You can select Allow all cookies to disable the "Block third-party cookies" option.

3. Click Add next to the "Sites that can always use cookies" option, then type your Oracle Cloud Application host domain in the Add a site dialog box and enable Including third-party cookies on this site. Click Add.

   Use the syntax [*.]OC_HOST_URL.com for your host domain in the dialog box to allow cookies from your host's subdomains.

   
   

   
   Description of the illustration trouble-addsite.png

   
   

   Confirm that your host domain is included in the list of sites that can always use cookies.

   
   

   
   Description of the illustration trouble-allow-cookies.png

   
   
4. Disable the "SameSite by default cookies" flag option by adding --disable-features=SameSiteByDefaultCookies to the browser's startup parameters.

   If you're using Chrome on a Windows machine, you can create a shortcut to Chrome and then add the parameter to the Target field in the shortcut's Properties window.

   
   

   
   Description of the illustration trouble-shortcut.png

   
   

   If you're using Chrome on MacOS, you can launch Chrome with the parameters from a Terminal window. To launch Chrome, open a Terminal window and type '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome' --disable-features=SameSiteByDefaultCookies.

   If you're starting Chrome from the command line, you can add the parameter when you launch the application (for example, /opt/google/chrome/chrome --disable-features=SameSiteByDefaultCookies).

5. Restart your browser and open the page again in the Page Designer.

After restarting your browser, you can open chrome://version/ in your browser and check the Command Line properties to confirm that "SameSite by default cookies" is disabled.

Description of the illustration trouble-chrome-version.png

How Do I Clear My Extension's Resource Cache?

Oracle Support might sometimes ask you to clear your extension's resource cache, so you can refetch its contents from the server. To do this:

1. Open the Menu in the upper-right corner of the header and select Settings.
2. Click Clear Client Caches under Troubleshooting.
3. If prompted to confirm, click Yes.

Clearing the cache removes persistent data stored in your browser and reloads the page.