Unreachable URLs

I have lot of unreachable URLs and erroors in my sitemap.
I don't undestand why are all this urls unreachable because when I click on them in WMT I can open them.

Hello Darko ,

Unreachable URL's means , Googlebot is having problem in reaching those urls. Make sure your host is not blocking GoogleBots

I am on dedicated server. How can I check that?

Just checked with host provider and they told they don't do any blocks on googlebot.
I am on dedicated server. Can I do something?

Then maybe it was a temporary glitch as all the entries are pointing to same date.