I had the same problem.  SM_7188 won't install.  I got lucky and found that it wouldn't work if you the .msi installer, but it would with the SM_7188.exe installer.

I found that the http://localhost:9998/ doesn't work, and it seems to be deprecated.  Should you want to used the :9998 website, it would install it under IIS with a 9998 binding.  Make sure you have the IIS role installed on your server.  That could resolve your issue.

I really like the new version, but it took a little tweeking to make the migration possible from 15.x and go to the most current version.  I am still doing testing, and it looks very promising.

-K

I'm not totally sure but if I remember correctly, port 9998 was when SmarterMail was installing a built-in web server. so it doesn't conflict with an already present IIS config.

Understand the port 9998 .. but the true issue was that it just "stalled" with the initial install.

It wasn't difficult to go around it.. but if I was a new user... not sure what I would have done.

Thanks Keevin & Sébastien  for the update.