EDIT: Please advance to later comments, I have found HOW this is happening, while I know how to fix each incident, I don't know where to fix it to prevent it from happening in the first place. https://www.virtualmin.com/comment/799479#comment-799479
Operating system Ubuntu 16.04.5 (GNU/Linux 4.4.0-131-generic x86_64) with all current available updates on this install.
Perl version 5.022001
Path to Perl /usr/bin/perl
BIND version 9.10
Postfix version 3.1.0
Mail injection command /usr/lib/sendmail -t
Apache version 2.4.18
PHP versions 7.0.30
Webalizer version 2.23-08
Logrotate version 3.8.7
MySQL version 5.7.22-0ubuntu0.16.04.1
ProFTPD version 1.35
SpamAssassin version 3.4.1
Webmin version 1.890
Usermin version 1.741
Virtualmin version 6.03
Theme version Authentic Theme 19.19
Error I am getting "SFTP connection error"
I have always created Virtual Servers the following way for the past 3 years and have had 0 problems until 2-4 weeks ago.
1) Create a Virtual Server, Use the default admin account created for the server for SFTP access (22) so that the hidden files like .htaccess can be modified and seen
2) Immediately create a stand alone user for database access using the "Add User to this server" instead of "Add a website ftp access user" so if worse came to worse, they did not have FTP access.
First, the problem, I use to be able to log in using the admin for the created virtual server without a problem, and I CAN do so, but ONLY before I create another user for that server. This took me a while to figure out since my process always had me creating the database user right after I created the virtual server, but to test to make sure that the SFTP was working, I deleted the virtual server and recreated it and tried to log in before I created the database user. Success, try to log in as the admin user of the Virtual Server after I create the user for database access and I get SFTP connection error.
Had no problems with this for the longest time like I said above. A server rebuild later, and still experiencing the same problem. The Virtual Server I am creating does not have e-mail hosting active, but neither do 99% of the servers on the system. Please help