Why is the euro exchange rate not loading?

Question

JavaScript

Greetings!
On the foldin site, on the second screen, there is a calculator for calculating the cost of walls.
If you click on Parthos Sliding Walls, the euro rate is loaded from the site https://www.cbr-xml-daily.ru
On some devices, the rate is not loaded (macbook, iphone 6). Although at the same time the course works on other devices.
I wrote a small condition that if the rate is not loaded, then it is equal to 75.
What could be the problem with loading the current euro rate?
I will be especially grateful if the owners of Apple products write here.

Answer 1

if the course is not loaded, then it is equal to 75

yes, according to the subject - debug, decompose:
it doesn’t happen “it works, it doesn’t work”
it happens “there is a connection, there is no connection”
“returns an answer, returns an error”
get used to thinking in these coordinates

Answer 2

Too few inputs. And I agree with the above.
For me, to be honest, it's not very clear.
Indeed, in fact, the process is divided into several parts
1) Send a request from the client / server or give the course from the client / server.
2) Parsing the course from the response.
3) We put the course in the block or wherever we need it.
In fact, the logic is simple - sent a request, received a response - changed the block.
Go through each step and see. Works / does not work on a particular device.
Having found the stage, we work even harder. Fix error. Check - no => fix again.
Putting the whole scheme together and into battle))