Well, I had a similar experience with... Coursera, a couple weeks ago, so I assume it affects the whole spectrum of customer support.
I was doing a course, and had to access a Jupyter Notebook that was residing in a different server. When clicking the URL, the page will appear with a loading circle, and would die out after around 5 minutes (I measured it).
I was using my laptop (W7 + Chrome) but have a server also running Debian, with Forefox as browser. Tested in both places before accesing the chat.
I put as much into in the chat before hand.
A person shows up, tells me to "clean cookies and cache".
Tell her about the different test (This was never acknowledged, BTW).
Tells me "must be your connection".
"OK, let me test with my G4 phone"
"That kind of connections can be what is giving you problems, try ADSL"
OK, this is getting funny now.
Tells me to test a different url that she sends me over the chat.
"OK, not working here, let me test in firefox"
"We advise to only use Chrome, our apps might not work in other browsers" (THEIR page stated otherwise, and it was not a browser problem)
Told her nothing works: Tested Chrome on W7 over G4, Firefox in Debian over ADSL, nothing.
"Coursera cannot take responsibility about the content, we can only support the apps" ???
So, I was having a chat with a support tech that couldn't tell one thing form the other, as it was obviously the server (Had tried other notebooks from the same course)
Finally, asked to raise this to 2nd level. Told me not to ask opther people to download the notebook for me, as in that case if I submitted my work this would be taken as if it worked.
A couple of hours later, I notice a "forceRefresh" parameter in the url, changed it's value, app starts working.
As a side note, based in my experience support people are not prepared to deal with people with a certain technical level on the customer end.