The Premium License was a App Store conversion. It has been running fine on two machines. During the initial conversion, the license was "bouncing" between each install. With this upgrade, the license is lost on both.
Same thing happened to me. I had to do a double-check to make sure I wasn't going nuts.
I was sure I paid until 2027. It's not just you. 
I'm sorry about the issue 
It is required that install 3.10 or later from App Store again, then switch back to Codinn Store version.
App Store version (3.10) is awaiting review by Apple, and should be available soon.
I'll send you coupon code to redeem license from Codinn Store, you can use the license before App Store version available.
Yang
This got me also. I guess I'll keep checking the App Store.
Craig, I just sent you a personal message with coupon code, please check.
Yang
Same with me
Version 3.10 was just arrived on App Store, please try reinstall Core Shell/ Tunnel, and then switch back to Codinn Store versions.
Sorry for the inconvenience.
Yang