The Preview Could Not Load Alert

[omid020]

Hi,

I’m using PRO theme and I decided to add a sidebar to homepage so in editor changed it “Content Left, Sidebar Right” but got this error :

I see this alert only on page templates with sidebar.

Then I checked Error Log and found these lines :

[16-Mar-2021 03:56:20 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxx/public_html/sitename/wp-content/themes/pro/cornerstone/includes/classes/common/class-locator.php:1) in /home/xxx/public_html/sitename/wp-includes/rest-api/class-wp-rest-server.php on line 1642
[16-Mar-2021 03:56:20 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxx/public_html/sitename/wp-content/themes/pro/cornerstone/includes/classes/common/class-locator.php:1) in /home/xxx/public_html/sitename/wp-includes/rest-api.php on line 675
[16-Mar-2021 03:56:20 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxx/public_html/sitename/wp-content/themes/pro/cornerstone/includes/classes/common/class-locator.php:1) in /home/xxx/public_html/sitename/wp-includes/rest-api.php on line 676
[16-Mar-2021 03:56:20 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxx/public_html/sitename/wp-content/themes/pro/cornerstone/includes/classes/common/class-locator.php:1) in /home/xxx/public_html/sitename/wp-includes/rest-api.php on line 677
[16-Mar-2021 03:56:20 UTC] PHP Warning: Cannot modify header information - headers already sent by (output started at /home/xxx/public_html/sitename/wp-content/themes/pro/cornerstone/includes/classes/common/class-locator.php:1) in /home/xxx/public_html/sitename/wp-includes/rest-api.php on line 678

Is it related to some server settings?

[prakash_s]

Hello @omid020,

Thanks for writing to us.

It seems that there might be an issue of plugin conflict, cache issue or WP Rest API is not working due to permalink settings or server settings. I would suggest you troubleshoot with a few of the common issues before we investigate your settings.

1. Testing For Theme Related Issue
2. Testing For Plugin Conflict
3. Theme Update
4. Child Theme
5. Css/Js Customization
6. Increasing Php Memory Limit
7. Disabling Cache
8. Disabling Cdn
9. Permalinks
10. Version Compatibility

If none of those work, It would be best if you could copying your live website to your staging area. and send your details in a secure note so that we can investigate your setting without breaking your live site. Please provide the following details

• WordPress Login URL
• Admin level username and password
• FTP Details

You can find the Secure Note button at the bottom of your posts

Thanks

[omid020]

Thank you @prakash_s! I tried all possible solutions but still see the same error on preview window. Please kindly check my content with following credential details.

Thank you in advance.

[tristup]

Hi @omid020,

I have visited your website and found that the Content Builder is loading perfectly for the pages. I have tried Edit with Pro from Page List, Edit with Pro button inside the page and from Pro > Content, every time the builder loads with the page and the content it has.

Can you please check once by clearing all the cache, and in incognito or private mode of browser. Please let us know if the issue still exists at your end.

Thanks

[omid020]

Hi @tristup,

I cleared cache and browsed in private mode but still see error with any option (Page Template) which is included Sidebar :

Regards

[tristup]

Hi @omid020,

I have checked your website page with the steps explained by you and found the issue. I would request you please copy your live site to a staging server so we could troubleshoot freely without breaking your live site.
And give us access in the secure note including:

– WordPress Site URL & Login URL
– WordPress Admin username/password

To create a secure note, click the key icon underneath any of your posts.

Thanks

[omid020]

Hi @tristup,

My website is on a test running , feel free to troubleshoot.

Thank you in advance.

[tristup]

Hi @omid020,

It seems you are using the Icon stack, and because of Icon’s unique layout, the template with sidebar is unavailable in this Stack. Please switch to another Stack if you need to make use of this feature.

Thanks

[omid020]

Thanks @tristup, Yup the Integrity Stack is Ok with Sidebar. I noticed when WPML plugin is activated Sidebar option does not work even on Integrity Stack and also Sidebar feature does not work under Appearance menu:

I see these comments on error log :

[24-Mar-2021 21:15:44 UTC] PHP Notice: Undefined variable: sitepress in /home/user/public_html/xxxx/wp-content/themes/pro/cornerstone/includes/extend/custom-sidebars.php on line 379
[24-Mar-2021 21:15:44 UTC] PHP Fatal error: Uncaught Error: Call to a member function get_element_language_details() on null in /home/user/public_html/xxxx/wp-content/themes/pro/cornerstone/includes/extend/custom-sidebars.php:379
Stack trace:
#0 /home/user/public_html/xxxx/wp-admin/includes/template.php(1389): ups_sidebar_do_meta_box(Object(WP_Post), Array)
#1 /home/user/public_html/xxxx/wp-content/themes/pro/cornerstone/includes/extend/custom-sidebars.php(321): do_meta_boxes(Object(WP_Screen), ‘normal’, NULL)
#2 /home/user/public_html/xxxx/wp-includes/class-wp-hook.php(292): ups_sidebars_do_page(’’)
#3 /home/user/public_html/xxxx/wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters(’’, Array)
#4 /home/user/public_html/xxxx/wp-includes/plugin.php(484): WP_Hook->do_action(Array)
#5 /home/user/public_html/xxxx/wp-admin/admin.php(259): do_action(‘appearance_page…’)
#6 /home/user/public_html/xxxx/wp-admin/themes.php(10): require_once(’/home/user/pu…’)
#7 {main}
thrown in /home/user/public_html/xxxx/wp-content/themes/pro/cornerstone/includes/extend/custom-sidebars.php on line 379

Is it a bug of theme?

Regards

[christian]

Hey @omid020,

I have replicated the issue and will post this in our issue tracker so this will be queued to be investigated by our development team. Regretfully, we do not have a solution right now so I’d recommend you use the Layout Builder instead as it’s translatable and you can create a custom layout so you can create a layout with sidebar.

Hope that helps.