I just downloaded a new version of WordPress 4.5.2 and started developing a theme but when I transferred it to the live I cannot upload images on the Post's featured thumbnail same as well on the Media Library.
When I try to upload an image on the Post's featured thumbnail I always got this error:
This seems like there may be a plugin activated that could be causing the error/conflict. I would recommend disabling all plugins to see if you can then add the images as expected. If that works, then try re-activating plugins one by one to see if you can track down which one might be causing and issue. Hope this helps.
Go to this post: There are some helpful troubleshooting steps there:
http://rockdio.org/ayudatech/solution-to-3-5-an-error-occurred-in-the-upload-please-try-again-later/
I found the problem in my functions.php. Good luck!
There are multiple reasons for occurring this error . For example memory issues , security permission issue or max file size issue.
Fixing errors when uploading images in WordPress
This above tutorial covers all basic reasons and solution for the problem .
