Migration assistant is asking for a volume password?

I don't know how more people aren't having this problem. I've looked all over the internet and support forums and found nothing helpful. Migration assistant is saying "In order to add new users to this system, we need to collect a password from an existing user who is already authorized." Then it's asking me for a volume password. I'm trying to migrate a standard user account between mac pro stations via our company network.

I'm the administrator, and I've tried using my credentials, as well as the user's credentials I'm trying to transfer, and nothing is working. I've verified that neither machine is locked with filevault, so there's nothing encrypted. I've tried using the network, as well as using a time machine backup. and I still get the same message. I've also tried enabling root user and entering those credentials. I can't even find information on what a volume password is.