Every time i try to buy premium,in the end i getting "You purchase cannot be completed" error.
I've tried 2 different apple id (russian & german) with no luck.
Screenshot:
I’m sorry for the problem, I did a quick test, and seemed everything works. From the screenshot, it’s very like a problem of Apple’s purchasing platform in your country.
Could you please follow the link in screenshot and ask Apple for support?
BTW, sometimes a system reboot can fixed problem magically.
I did it several times, same error happens again and again. I’ve contacted apple support, let’s see.
Great, please update thread if you get response from Apple.
But for me it looks like app bug, because most of the time if i click buy subscription in app dialoog window, app (dialog window) just freezes, i can quit app, but all buttons in dialog window just disabled and nothing happens. I can provide console logs if you want.
And only after reboot i can proceed and get error.
Could you please take a look at this article:
Though the article is iOS specific, the solution might similar.
It’s amazing, i’ve have bought subscription from another absolutely same macbook, then i’ve restored it on my macbook.
That’s great 
thanks a lot for purchasing!
Did you get response from Apple?
Not yet, they promise me to investigate that problem, and for now just suggested to reboot)
I got exactly the same error message when trying to purchase the subscription - a reboot did not help. So I’ve raised a ticket with Apple.
I’ve sent you a code to enable premium features, please feedback here if you receive response from Apple, thank you!
Hi Yang,
I've just tried to buy a license today, but it looks like this feature still doesn't work for me:
Is there another way I can pay for this?
Kind regards,
Ben
Hi Yang,
I've solved this by uninstalling and re-installing the app, and now have been able to purchase via iTunes.
The unfortunate side effect is that it did not read my sync folder on re-install, so I lost existing configs.
However, I'm glad I've been able to pay for this, because last year you gave me a free license to get around this issue.
Kind regards,
Ben
Hi Ben, have you get your configuration back? The sync function should come back after you purchase a premium license, and a reinstallation generally won't sweep your configurations.
Please let me know if you need my assistance to get your data back.
Yang
Hi Yang,
Unfortunately the re-install did not seem to recover the previous config (which was sync'ed to a folder).
However, I figured it would easier to re-create the tunnel definitions than try to recover everything, so I didn't spend much time looking into the recovery - potentially I overlooked something there.
But in any case, all is good now.
Ben
Good to know it didn't affect your work too much, please drop me a line whenever you need help.
I have the same problem. I would like to buy the 4 year premium plan, but I am getting this app store error. I can't reinstall because I will loose all my current setup and I don't have the time to recreate it.
Is there a way of exporting without premium? I really need a backup before reinstalling.
Generally, reinstallation won't wipe your data, but in case on the safe side, you can backup these two folders:
~/Library/Containers/io.coressh.tunnel/Data/Library/Application\ Support/io.coressh.tunnel
~/Library/Group\ Containers/E78WKS7W4U.io.coressh.ssh/
And copy back after reinstallation.