Brett

Did you make any changes to your web host, add any additional plugins, or modify the .htaccess file in any way?

You will find the code here on the Post Thumbnails Codex page.

TwentyEleven used, if I am not mistaken, the header graphic was the placement of the Feature image. Given that this is a child theme and looks much different than the Parent, you or the theme designer would need to enter the code for Featured Images to display.

Well, when you make a post, is there a Featured Image box in the Editing Screen? Second, wherever you downloaded the Theme, does the Theme information mention the inclusion of Featured Images?

Sorry for the obvious question here, does the TwentyEleven Child theme you have installed have Featured Images enabled?

Could you de-activate the Yoast SEO Plugin and try again? Also, what Theme are you using?

If the login is no longer working, I would try contacting your web host.

That is interesting. If the account you are using is indeed an Administrator role account, you should be able to see the Users menu panel in the backend Dashboard.

It could be a plugin conflict with the X Theme. You might want to get in touch with the Theme Author to check if there is a conflict.

You could look into Membership Plugins such as Paid Memberships Pro that set categories to private based on membership level.

If the only Administrator user is out for two weeks, you have two options: (1) Wait for them to return, or (2) ask if they can login from where they are and assign you as a higher role.

No problem. The process is as follows:

1. Downloading WordPress installation files from www.ads-software.com
2. Uncompress the ZIP file downloaded in your Downloads/Desktop folder
3. Using an FTP program (like Filezilla) upload your files to the webhost.
4. Remove the wp-admin & wp-includes folders. Leave the wp-content folder untouched.
5. Upload the wp-admin & wp-includes folders and files that you had one in step 1 to the web host.
6. Login and try again

You can see directions like this on the WordPress Codex: Uploading WordPress to a Remote Host.

Before this became a problem, did you add any new plugins?

Are you able to use an FTP application to connect to your webhost and remove it from the wp-content/plugins folder?

I would recommend upload a fresh set of WordPress files on your web host.