Based on the error, I'm assuming you're using floating license for Ready API. If that's the case more users might be connected to the license server at this time that the number of licenses your organization has.
That doesn't mean that you've to jump the gun to request purchase of additional licenses. Talk to who over manages your floating license server. Mostly they can pull out the list of users who are using floating license, and request who ever is not actively using it to check the license back in. If they can't find who all are using licenses, the account manager on SmartBear side can help you do this. Every company who has purchased a license will have an account manager on smarbear side.
Talk to who ever owns license in your organization. They would be able to help you.
Cheers!
Gilu Gopi