I donwload and I am using adminer plugin, but I can not connect :-(
server name is same as name in wp-config.php
nick and password are ok, I am sure :-)
So where is problem ?
I guess that you have provided a wrong server name. It should be db50.websupport.sk, I can see some other character (probably slash and something else) behind it.
Some servers also use different port which can be specified by server:port notation.