Bonjour Perrine,
You mentioned in your previous message that "Converter and source machine are not on the same LAN. The helper is configured to be on the same LAN than the source."
I thought that may be, if converter is in the same LAN too, the problem would not appear anymore. Actually the error occurs in the communication between converter and helper. The idea was, that if they are in the same LAN, the error may disappear.
We have discussed the issue with Ivan (ivivanov) today. The possibility of IP conflict is not ruled out yet. Can you check the static IP you have tried with is not in the DHCP range ? Also, is it possible there is more than one DHCP server in the LAN ? If it is not an IP conflict, no other idea unfortunately.
Since the source is a VM, can you power it off and do a V2V conversion instead ? (It it less functional indeed, you can't unselect or resize volumes, do disk alignment). If this is a possibility, please take into consideration you may need to open port 902 in the firewall.
Regards,
Plamen