SSH proxy KO

Hello,

I configured an SSH proxy on our F5 BIG IP. 

I follow all instructions of https://techdocs.f5.com/kb/en-us/products/big-ip-afm/manuals/product/network-firewall-policies-implementations-12-1-0/13.html.

When I test the connection, I have the message "Network error: Software caused connection abort"

On F5, I see this log at each request:

err sshplugin[14513]: SSHPLUGIN: sshplugin_0|SSHPlugin|sshplugin_client_handler|Core|Error listening to socket: ECDSA, DSA, or RSA host key file must be set

I check on the F5, I could connect to the final server on sftp with the right key exchange (we use ECDSA and not RSA). The key is in the known_hosts file with the right key and IP.

I must forget something but I don't know what.

Thanks in advance for your help!