port forwarding to IPv6 target fails

The following command works just fine to escape an IPv4 environment and reach an IPv6 target:

ssh -N -p 22 user@example.com -L 127.0.0.1:2222:[2601:646:8182:7d:82:9bff:3ef2:1084]:22

However when I configure the same node and account in Remote Desktop Manager as an SSH gateway it always fails:


[5/16/2018 1:54:08 PM] Starting SSH negociation
[5/16/2018 1:54:08 PM] channel_open: Creating a channel 43 with 64000 window and 32768 max packet
[5/16/2018 1:54:08 PM] ssh_connect: Socket connecting, now waiting for the callbacks to work
[5/16/2018 1:54:08 PM] socket_callback_connected: Socket connection callback: 1 (0)
[5/16/2018 1:54:08 PM] ssh_packet_channel_open_fail: Channel opening failure: channel 43 error (1) open failed
[5/16/2018 1:54:08 PM] Unable to connect remote end of tunnel: aborting connection localhost:0 -> [2601:646:8182:7d:82:9bff:3ef2:1084]:22
[5/16/2018 1:54:08 PM] ssh_socket_exception_callback: Socket exception callback: 1 (0)
[5/16/2018 1:54:08 PM] ssh_socket_exception_callback: Socket error: disconnected
[5/16/2018 1:54:08 PM] Error connecting to server: [5/16/2018 1:54:08 PM] Socket error: disconnected[5/16/2018 1:54:08 PM] Disconnecting from SSH server
[5/16/2018 1:54:08 PM] Disconnecting from SSH server


Same problem if I use a hostname that only has an AAAA address too FYI.