Can't install Photoshop plugin because Anastasiy's Extension Manager gives -955 error

I'm trying to install a plugin into photoshop, but the plugin is a .zxp file. So I install Anastasiy's Extension Manager to install it, but it then says it has an error and it couldn't finish the installation. 

The error is a -955 error, an error that doesn't even show up on Adobe's or Anastasiy's FAQ or troubleshoot page. If people know what this error means or how to fix it, please let me know and I will appreciate it. Thanks