problems uploading media

Hello,

I am working with the Oyster WP theme and an unable to upload any media. I have uploading in every format and size but am still seeing the grey box or the little blue box with a question mark.

I am also unable to download plugins. I receive the following message:

Unpacking the package…

Could not create directory.

Please see the website in question below.

https://www.haroldschouten.com