Help! Trouble with uploading and Updating plugins

hello,

I need help .. i am a virtual assistant that maintains a wordpress website, which is ioannis.org and my boss who owns the site tried to upload a jpg at the Media library and he gets an error. he gets an error when trying to update plugins.

he had to do the uploading through https://managewp.com/

this is the address of the WP-egine account: https://my.wpengine.com/installs/ioannis

We badly need the feedback. Thank you! ??