Can you please Share you Target Account Login credentials in a private message so that we can debug the issue at our end.
Thanks & Regards
What was the solution to this as I am having the same issue, with two different companies?
Also, I get a similar message when attempting to delete hosts, are there any prerequisites needed so someone can use the hosts and environments?
Please check the Target user permissions of the user who is trying to move the host to a different environment.
A user should have "Approver" rights for the workspace associated with the domain you are moving. This worked for me. Hope that helps.
We do have a currently open bug with our engineering team for this issue where we are not being able to move hosts. We expect the fix to go out in the next maintenance release(in September).