Can view Widgets admin page but cannot edit entries

Are there any errors showing in the inspector console when you inspect the page? Try pressing F12.

This may be a plugin or theme conflict. Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.

I’ve drastically cut back on the number of active plugins to 20. What’s strange is that I also cannot change the theme. I can select something like Twenty Fifteen but nothing changes. I strongly suspect that I cannot change the theme because my site uses a special LeadPages plugin to display a customized LeadPage as my home page. Nevertheless, I was able to add and edit widgets months ago with the same LeadPage plugin installed.

This might very well be a clue (I didn’t include all the script errors, which were numerous).

Mixed Content: The page at ‘https://www.MYSITE.com/wp-admin/widgets.php’ was loaded over HTTPS, but requested an insecure stylesheet ‘https://ajax.googleapis.com/ajax/libs/jqueryui/1/themes/ui-lightness/jquery-ui.css’. This request has been blocked; the content must be served over HTTPS.

Uncaught TypeError: Cannot read property ‘hasClass’ of undefined
at HTMLDocument.<anonymous> (load-scripts.php?c=0&load[]=hoverIntent,common,admin-bar,jquery-ui-draggable,jquery-ui-droppable,admin-widgets,svg-painter,heartbeat,wp-auth-check,thickbox,&load[]=media-upload,mce-view,imgareaselect,image-edit,quicktags,wplink,jquery-ui-position,jquery-ui-menu,jquery-ui-autocomplete&ver=4.8.3:269)
at HTMLDocument.dispatch (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,underscore,shortcode,backbon&load[]=e,wp-util,wp-backbone,media-models,plupload,wp-plupload,mediaelement,wp-mediaelement,media-views,media-editor,media-audiovideo&ver=4.8.3:3)
at HTMLDocument.r.handle (load-scripts.php?c=0&load[]=jquery-core,jquery-migrate,utils,jquery-ui-core,jquery-ui-widget,jquery-ui-mouse,jquery-ui-sortable,underscore,shortcode,backbon&load[]=e,wp-util,wp-backbone,media-models,plupload,wp-plupload,mediaelement,wp-mediaelement,media-views,media-editor,media-audiovideo&ver=4.8.3:3)

I think this is where the problem starts:

‘https://ajax.googleapis.com/ajax/libs/jqueryui/1/themes/ui-lightness/jquery-ui.css’. This request has been blocked; the content must be served over HTTPS.

Did you recently switch to https?

This would be a lot easier if you told us the URL for your site.

While I recently obtained an SSL cert and switched to https, the widgets access problem affected my site beforehand, not afterward. Below is the url to my home page:

https://www.organicsulfur4health.com/

OK, so if it was beforehand, then it’s probably not that.

This may be a plugin or theme conflict. Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.

See https://www.wpbeginner.com/plugins/how-to-deactivate-all-plugins-when-not-able-to-access-wp-admin/

I think I may have found the source (or at least a clue) of the problem. I looked at the file structure of my site and noticed that my theme contains a folder called custom-sidebars. Within custom-sidebars I found another folder that is nested one level below that has the same name (custom-sidebars). The nested folder also contains an identically named folder called tpl.

Here’s another error message that I see when access console using F12:

Uncaught TypeError: k is not a function
at HTMLDocument.c (editor.min.js:1)
at i (load-scripts.php:2)
at Object.fireWith [as resolveWith] (load-scripts.php:2)
at Function.ready (load-scripts.php:2)
at HTMLDocument.K (load-scripts.php:2)

I believe I’ve narrowed the problem down to an issue with JavaScript on my site. None of the Widgets buttons activate to bring up a drop down menu when I click on them, unlike those in the Menu section that work fine. I’ve logged onto my admin page using the macOS as well as Windows 7 and I encounter the same response. Perhaps reinstalling the theme will fix the problem?

I stumbled upon a rather strange solution to my widget problem. I logged into the WP admin page using one of the Hide My Proxy websites and was finally able to get access to the widgets and make the edit changes I wanted. Going in normally never worked for me. I tried both wifi and wired and used different browsers, operating systems, as well as my cell phone without success. What led me to the proxy idea was after I spent time emailing the theme’s lead developer, who had no problem making mock changes to my widgets after I gave him temporary admin privileges. Something about my network address was hindering my access to this (and only this) menu screen. Anyway, the problem is resolved, for which I’m grateful.