Hello,
My operating system is Ubuntu 20.04.
After installing aapanel, even though I install the Mail Server program from the store, it is not installed on the server.
That is, the installation process is created, but after the end, we see that it has not been installed.
Please guide me, what is this problem?

    mhosseint what is you vps spec?
    I think your installation auto killed if your ram too small