Unable to Connect

I use the Filezilla FTP and have had no problems with it connecting. Tonight when I logged on to fix some errors all it gives me is “Unable to connect”. I’m not sure if this is a problem on my end, was wondering if anyone else is having this problem? I get connections errors while trying to access thing on my site all the time and other people have sent me emails saying the same. So I’m just basically curious who is responsible here DH or my ISP. If I’m the only one I’d like to know.