Unable to update plugins and upload files

Hi James,
I have five WP sites on my stage server that I usually test the updates before, updating the production sites.

I had a problem with four of them, I was able to fix the issue for three of them by adding the code form http://wptavern.com/how-to-fix-images-not-loading-in-wordpress-4-4-while-using-sslto the function.php which solved three of my sites.

I am getting this error (Unable to create directory wp-content/uploads/2016/01. Is it parent directory writable by the server? And the answer is yes, it’s writable) only on one of my sites. The above code did not help at all for this site. It looks like a permission error, but, I didn’t change anything in my server, and all other sites are running under the same server. Folder permissions are ok the way was before with no problem.
The parent theme for this site is twenty twelve updated to latest version. I changed the theme, deactivated and activated the plugins with fresh install, but none of them make any difference.
Do you have any suggestion or advise?

Appreciate your time and help in advance.

yes, it is. Everything works fine, but uploading images to media library.
I was able to update the plugin via ftp.

The other sites had displaying issue with image which that code fixed the issue.
Thank you