[phenixbb] You appear to have another session of Phenix running already

Hi all, I have been experiencing this issue when I start phenix *"You appear to have another session of Phenix running already (hostname=.....), which has locked your project database to prevent corruption. If this is the result of crashing or killing the GUI, you can continue, but only one session should be run at a time. Do you want to override the lock?"* It gives me two options, either No or Yes, neither one starts the Phenix. I wonder if anyone else knows how to fix it. Thank you! Best Kaoling Guan