SFTP transfers fail

What is the problem you are having with rclone?

When trying to copy or move large files (i.e. 100GB+) transfers fail after about 20 minutes with the error messages below. This happens whether 4 or 20 files are being transferred. It also doesn't matter whether it's a normal or crypt remote.

The problem seems similar to Crypt + SFTP - failed to send packet: EOF & Slow! - #5 by ncw

What is your rclone version (output from rclone version)

rclone v1.55.1
- os/type: windows
- os/arch: amd64
- go/version: go1.16.3
- go/linking: dynamic
- go/tags: cmount

Which cloud storage system are you using? (eg Google Drive)

SFTP - rsync.net

The command you were trying to run (eg rclone copy /tmp remote:tmp)

rclone move P:\ remote2: -P -vv

The rclone config contents with secrets removed.

[remote2]
type = sftp
host = xxxxxx.rsync.net
user = xxxxxx
pass = xxxxxx
use_insecure_cipher = true
md5sum_command = md5 -r
sha1sum_command = sha1 -r

A log from the command with the -vv flag

2021-06-02 14:00:49 DEBUG : sftp://xxxxxx: Not closing 4 unused connections as 20 transfers in progress
2021-06-02 14:01:05 ERROR : sftp:xxxxxx: Discarding closed SSH connection: read tcp xxxxxx: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
2021-06-02 14:01:05 DEBUG : sftp://xxxxxx: Connection failed, closing: failed to send packet: write tcp xxxxxx: wsasend: An existing connection was forcibly closed by the remote host.
2021-06-02 14:01:05 DEBUG : xxxxxx: Failed to remove: failed to send packet: write tcp xxxxxx: wsasend: An existing connection was forcibly closed by the remote host.
2021-06-02 14:01:05 ERROR : xxxxxx: Failed to copy: Update ReadFrom failed: failed to send packet: EOF
2021-06-02 14:01:05 ERROR : xxxxxx: Not deleting source as copy failed: Update ReadFrom failed: failed to send packet: EOF
2021-06-02 14:01:26 DEBUG : pacer: low level retry 1/10 (error couldn't connect SSH: dial tcp xxxxxx: connectex: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.)
2021-06-02 14:01:26 DEBUG : pacer: Rate limited, increasing sleep to 200ms