Tumblr widget error

Hello,

Thank you for this widget ! Tumblr widget cannot work on my blog also I read rhe “installation” section and isn’t working.
After download the widget, when I tap tumblr widget in the search bar on my account I can’t found it … Why ?

Thank for the help.
I use Adelle theme (I don’t know if it is a problem)

https://wordpress.org/plugins/tumblr-widget-for-wordpress/