Pending - Waiting for next available executor

I am using Jenkins version 2.271 and I’m having issues running jobs on one of my server. Even though there are no job in the queue for the system, Jenkins keeps showing ‘pending - Waiting for next available executor’.

I have checked in google but still i didn’t get solution.

Jenkins 2.271 is a weekly release from Dec 2020. You’re much more likely to receive help if you confirm that the same problem exists on the current weekly release or on the current LTS release. In this specific case, you’ll need to provide more information before others are likely to offer their help.