Plugin no longer working after WP 4.1

I did the update to WP 4.1 and now the constant contact plugin doesn’t work, and it doesn’t even show up in my list of installed plugins. I tried manually downloading the plugin and uploading it to my plugins, but it fails and says that this plugin is already installed, but it still doesn’t show in my list of installed plugins. Here is a copy and paste of what it says:

Destination folder already exists. /home/content/24/10629624/html/wp-content/plugins/constant-contact-api/

Plugin install failed.

https://ww.wp.xz.cn/plugins/constant-contact-api/