When to do a Graceful Exit

Good day!
How do I know when to do a Graceful Exit?
After what period is it available? 15 months?

When I try to execute Graceful Exit, I get the following message:
You are not allowed to initiate graceful exit on satellite for next amount of months:
Error: You are not allowed to graceful exit on some of provided satellites

This is our most recent Graceful Exit Guide. If you need further assistance please let us know.