Duplicate Post PI

I uploaded the Duplicate Post PI, said upload successful, but when I search for it it isn’t in my PI menu. Tried to upload again thinking maybe I read “successful” wrong –but no, upload failed because it says it’s there already. Can’t find it. This is the message- Help! not a pro:

Destination folder already exists. /home/content/38/7077038/html/dev/wp-content/plugins/duplicate-post/