so i am having a issue with a few sites not working on my pc's but they work mobile i need these to work can someone please help me out. it says The connection has timed out

The server is taking too long to respond.

What can you do about it?

• The site could be temporarily unavailable or too busy. Try again in a few moments.
• If you are unable to load any pages, check your computer’s network connection.
• If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the web.

i reset my dns and cleared cache and i am stumped please help