gif file error, gif won't upload?

What is the exact error you are seeing in the FTP Log (open the panel under Window > Results > FTP Log) when you try to upload?

Filezilla is a good alternative to DWs sometimes finicky FTP functionality, but if the problem is permissions-based which "just started happening upload issues" usually are, you'll need to contact your hosting company to repair them even if you get Filezilla.

The exact message from the FTP Log will usually shed light on what needs to be repaired.

While you troubleshoot, use Filezilla  FTP client to transfer files to server. 

https://filezilla-project.org/download.php?type=client

If that fails, then there is a problem with the host server or something between your computer and the host server.  Check your log-in ID and password to be sure it's correct.  Also ensure there is ample free space on the server.  If the server is full, it cannot accept new files.