Question:
On the client side, SFTP access to FileZilla has recently been discontinued. It reports as an error: "Connection timed out".
This also stopped SSH access to PuTTY. The error is the same. This is definitely on the client side, since it connects successfully from another machine. Avast antivirus, but it was still there when there was access. Windows firewall is disabled.
Answer:
perhaps somewhere along the way, packets are being blocked based on the port number.
try on the server in a program that implements the ssh protocol to specify another port for incoming connections and specify this port in the client program.
if the program is listening in the openssh implementation, then in the file /etc/ssh/sshd_config you can specify several ports like this:
port 22
port 12345
...
the program after making changes, of course, needs to be rebooted.