Problem connecting to websites with SBS 2011

Your default gateway IP address must your router IP Address.

Restart your dns client service if still issue persits then add your ISP dns server IP Address in alertnet dns server or 4.2.2.2 then check.

Sorry, the router is the default gateway. And I have 8.8.8.8 and 8.8.4.4 (google) as.forwarders in my DNS server.

The strange thing is that internet is working, and I get results when performing nslookup. But the website isn't loaded.

I tried all the solutions for DNS problems with SBS2008 but no results.

post ipconfig from a workstation

why don't you use your ISP's DNS servers in the forwarders?

you could also use tracert tools, is nslookup reasonable?  
What if you try and access the website by ip address

@WORKS2011: See attachment. I tried also the DNS servers from the ISP but with no result
@ve3ofa: When I do a trace it completes, same as a nslookup (see attachments). When I try the IP address the result is te same... Waiting for website...

note:  one of the site which isn't working is www.binsearch.info
ipconfig.png
nslookup.png
tracert.png

have you tried the FritzBox support ?? http://www.fritzbox.eu/en/news/2012/new_support_numbers.php

I think it is router related.

I don't think it's router related because before SBS2011 everything worked fine, nothing has changed on the router.

are you trying this from a networked machine or the server  if the server do you have internet explorer security configuration turned on?

is it always the same sites?

Always the same site, from every station and server.

if it is a public site could I have the address and try it here?

You mean the url? Www.binsearch.info for example

Do ipconfig /flushdns on the server, right click on the DNS Server select "scavenge stale resource records", "update server data files", and "clear cache", go to "All Tasks" and select restart then test.

I would reconfigure DNS forwarders for testing purposes to your ISP DNS servers. It sounds like something isn't correctly resolving between your server and the forwarding servers, for testing purposes change and post the results. Google DNS is great but it's been known to have an issue here and there the only way find out is remove it from the equation while troubleshooting.

There is an issue with DNS not being able to resolve some top level domains.  You may wish to review and see if it applies to your configuration.
http://blogs.technet.com/b/sbs/archive/2009/01/29/cannot-resolve-names-in-certain-top-level-domains-like-co-uk.aspx

@WORKS2011: Google is out! Erased and flushed everything restarted the complete server but no result.

@RobWill: This was also the case with SBS2008 and I already did that.

Extra note: The URL is resolved if I nslookup the website. See attachments above. So the DNS is resolving the URL, but nothing happens after that.

Router is not blocking anything. Firewall also no problems there checked all rules.

I tried Google Chrome and Safari on a Mac same results.

Problem resolved itself. Still don't know how and why.