I'm developing an old wordpress website. There I can not upload any theme/plugin. I mean there's no add new option for plugins and themes. I updated it to the latest 4.7.1 version but still no luck. In config.php file there's no DISALLOW_FILE_MODS or DISALLOW_FILE_EDIT such option defined. I can't figure out where this disable option came from?
Also it's uploaded on a sftp server. I can manually upload any plugin to wp-content/plugins folder through sftp but after activating the plugin it makes the website frontend white screen death.
Overall, how could I allow theme,plugin uploading or how could I allow add new options to them?
Reading around the web about this, it seems like this might be caused by not having enough resources to operate, so I assume WordPress checks for this and disables in advance the ability to add new content.
I suggest checking the following values in the php.ini config file (you can run a script containing <?php phpinfo() ?> from the server to see the values faster; just don't make it publicly accessible):
display_memory - should be at least 128Mmax_post_size - by default is 8M, try setting it to 128upload_max_filesize - by default is 2M, try setting it to 128