In order to troubleshoot such issues you have to check the internet connectivity to your server. Here are some tips:

• Run ping and traceroute checks. Compare the results with other sites. Usually results with less than 200 ms are fine and do not indicate problems;
• Try working in your control panel (cPanel, Plesk, Vdeck, etc.);
• See how fast mails download.

Most shared hosting servers are situated in the USA which is a priority destination for all Internet service providers. You can find where your site is hosted from here.Connectivity affects greatly your site when on it you have:

• Flash animations;
• Big graphics;
• Huge file downloads.