OK.
Try using Google DNS server:
1. Open System Preferences and Then Click the Network icon.
2. Select your active network connection on the left, and then click Advanced
3. Click on the DNS tab
4. In the DNS Servers section, click the [+] button on the lower left
5. Type 8.8.8.8 and press enter
6. Click the [+] again, and type 4.4.4.4 and press enter
7. Click OK and then Apply
Your computer will now use Google's free DNS servers instead of your router/ISP's servers. Test it out, if you still have problems, simply follow the steps above but delete the 8.8.8.8 and 4.4.4.4 entries (highlight each entry and click the [-] button on the lower left). Your computer will return to using the default DNS server.
Also you may try to type the pair of IPs 208.67.222.222 and 208.67.220.220
Try using Google DNS server:
1. Open System Preferences and Then Click the Network icon.
2. Select your active network connection on the left, and then click Advanced
3. Click on the DNS tab
4. In the DNS Servers section, click the [+] button on the lower left
5. Type 8.8.8.8 and press enter
6. Click the [+] again, and type 4.4.4.4 and press enter
7. Click OK and then Apply
Your computer will now use Google's free DNS servers instead of your router/ISP's servers. Test it out, if you still have problems, simply follow the steps above but delete the 8.8.8.8 and 4.4.4.4 entries (highlight each entry and click the [-] button on the lower left). Your computer will return to using the default DNS server.
Also you may try to type the pair of IPs 208.67.222.222 and 208.67.220.220