I'm trying to migrate our on-prem Jira Software instance to the cloud. Unfortunately, I'm running into all sorts of trouble with the migration assistant.
When I try the "Assess and prepare your users", I get this message:

If I try to jump ahead and migrate just the users, I get this message:

Messages include:
We couldn't check for Jira Work Management availability in cloud
We couldn't check for Jira Software availability in cloud
Some required URLs need authorization for migration
We couldn't check for invalid users
We couldn't check Jira Software user limit of your cloud plan
We couldn't check for Jira Work Management user limit of your cloud plan
The server has full access (outbound) to the Internet and I'm not seeing anything blocked on the firewall.
Unfortunately, our Jira instance is small with only 10 users, so I don't qualify for support. It's super frustrating.
Any help would be appreciated.