Code2 error 403 Forbidden when click Save

[rumen]

mod_security was off, but other custom mod was on and blocked half of the modules. So it was solved!

[dbs]

Could be your hoster has activated mod_security.

[rumen]

I got super strange problem.

1. When click Save on module Code2 I get error 403 Forbidden. I checked and saw with the ISP mod_security is not an issue. Files 644, folders 755 - checked.

2. I have <IFRAME> on the home page in Code2 module. It doesn't appear. I took the <IFRAME> code and checked in HTML editor - appear normally. In the internal page there is <IFRAME> in Code2 module and there is no any issue - appear normally. When I decided to check with different browser I saw that on the first page the <IFRAME> appear in FireFox but don't appear in any other browser.

Any ideas?