aaPanel_Jose hello, ty for ur work
but I have aapanel 6.6, and I had the latest version of mail server plugin
but when I clicked on it I get this error
I uninstalled mail server plugin, and I tried to install it again
but when I hit install, i get installation failed message
no need to answer, i restart server and panel
and i checked i already had mail server 2.6
i dont know how, but problem solved