[Solved] Bad Request This web server is running in SSL mode – Webmin –centos 7

With SSL disabled, you can access the Webmin panel over a standard HTTP connection.

Here I’m explaining the steps to disable SSL from server backend (Command Line Interface). See the steps explained below:

Step 1: SSH to server as root user

# ssh root@IPaddress

Step 2: Open the configuration file with your favorite text editor. The configuration file for Miniserv is “/etc/webmin/miniserv.conf.”

[root@crybit #] vim /etc/webmin/miniserv.conf

Step 3:  Change the value of  “ssl” entry from 1 to 0

ssl=1 to enable
ssl=0 to disable 

Step 4: Restart Webmin service.

[root@crybit #] systemctl restart webmin

Step 5: Restart Apache

[root@crybit #] systemctl restart httpd

sumber :https://crybit.com/how-to-disable-ssl-on-webmin/