Ajax errors occur with a lot of customers

[dima_tr]

Hello, everyone. 

 

My shop has been working for half a year. My conversion rate was not high and I decided to figure out why.

I added yandex webvisor system to my site that tracks behaviour of my customers.

 

I figure out that many customers face ajax errors while trying register or adding product to the cart:

 

alert#1 Impossimble to add the product to the cart 

alert#2 technical error unable to load form

 

 

1) On many computers and browsers I use I cannot reproduce errors (including Ipad and Iphone). For me everything works fine.

2) On those computers I do not have firewall.

3) I didnot dramatically modify default theme templates (so problem is not here). 

4) I disabled mobile version.

5) I turn on friendly url.

 

Help please with some clues. Maybe firewall is causing problem?

 

Screenshot is attached/