Can't stay connected via SFTP

[Mick Morrissey]

When I connect to my A-Drive account via SFTP I can't stay connected long enough to do anything. I can't open any folder that has more than a few files in it before the connection times out and resets. The connection times out after 20 seconds, and Filezilla can't open a folder and list its contents in 20 seconds if there are more than a very few files in it. Sometimes even when there are only a few files or sub-folders.

I had no trouble like this when I started using Filezilla a month or two ago, but since early this week it happens every time.

I am using the latest version of Fileailla, 3.33.0. I just updated from this site yesterday, and updating makes no difference.

This is what the log looks like. Picture the same entries repeating over and over, and that's what I get when I keep trying:

Status: Connecting to sftp.adrive.com...
Response: fzSftp started, protocol_version=8
Command: open "mmorr99@…@sftp.adrive.com" 22
Command: Pass: *
Error: Connection timed out after 20 seconds of inactivity
Error: Could not connect to server
Status: Waiting to retry...
Status: Connecting to sftp.adrive.com...
Response: fzSftp started, protocol_version=8
Command: open "mmorr99@…@sftp.adrive.com" 22
Command: Pass: *
Status: Connected to rsync.adrive.com
Status: Retrieving directory listing...
Status: Listing directory /home/mmorr99@…
Status: Directory listing of "/home/mmorr99@…" successful
Status: Retrieving directory listing of

"/home/mmorr99@…/SOFTWARE"...
Status: Listing directory /home/mmorr99@…/SOFTWARE
Error: Connection timed out after 20 seconds of inactivity
Error: Failed to retrieve directory listing

[Tim Kosse]

Cannot reproduce.

There must be a firewall or NAT router on one end of the connection that drops the connection.

This must be independent of the most recent update as no code related to SFTP has been changed at all.