Components not loading on some clients

[astidis]

Running Prestashop 1.5.6.1 with a template from TemplateMoster.com. URL is http://samos.agliafs.com

 

I have had feedback from some customers that their website was not loading since launching my site 12 months ago. This week I was able to replicate the situation where the home page takes over 10 seconds to paint, then never finished painting the navigation bar and the TM slider module displays text without the background fill.

I was able to reproduce and work around this issue with the following steps:
- With PC connected to Internet via ISP and home router
- Clear browser history
- Open page
- Page does not load

Then I disable the ISP connection and connect the same PC to the Internet via a smartphone hotspot
- Page loads immediately and all components load

I return PC back to ISP
- Pages continue to load properly until cache is cleared then problem reoccurs

I have attached a screenshot of a half painted home page for your reference.

My question: Do some components of the Prestashop engine or template load from a component host server that may be blocked by some ISPs? How can I diagnose this?
 

[dioniz]

I tested your site and it works great in FF. Cleared cache and it works