Hi,
This happened to me before, right after I moved my neos to a new bigger more beautiful/fancy cage. After 3 days of staying on the ground, (after repetitively putting them back on the perch) I gave up and moved them back to their original smaller bare looking cage, and they perched immediately.
I felt that it was kind of an insecurity thing, and the behavior is mmm...... shall I say "individualistic" since my other neos did not exhibit the same thing.
Sooo, I grew them a little more in the smaller cage, then when they were noticeably much bigger, I moved them to the same bigger cage, they perched and were on strike poses the day I moved them and everyday after that.
Any particular reason you moved them to a bigger cage?
regards,
Arnold