Error loading page

Centos 4,5, latest Virtualmin Pro 50
Few days ago I got the typical error page accessing via web to my server:
"Error loading page
Cannot connect to server ... or the server is overloading ... bla bla "

All websites are working, and I still receive mails form server about updates.
But simply I cannot access to virtualmin via web interface.

Notes:
1) I have set virtualmin/webmin to auto-update and install security releases but not normal updates.
2) I have changes address port from 10000 to 10001 (but i tryed to access using different ports with same result)
Maybe last update crashes web interface ?

How to check via Telnet/ssh ?

Status: 
Closed (fixed)