Saved SFTP connections no longer working with Xfinity internet

I have some saved SFTP connections which were working with my previous internet provider but are no longer working since I have switched over to Comcast Xfinity for internet.
When trying to connect with SFTP with FileZilla I initially get a response from the server 
"Response: fzSftp started, protocol_version=9"
But then I get the following errors. 
Error: FATAL ERROR: Network error: Software caused connection abort
Error: Could not connect to server
Status: Waiting to retry...

When I change my FTP settings and switch from SFTP to passive FTP I am able to connect. 
I do not want to use FTP connections that are not secure and need to continue using SFTP connections to servers.
Is this something I can fix in my xfinity network settings? Or is this something that is being blocked or that I need to contact customer service about?