Seemingly bizarre DNS server could not be found responses

[telemus 16]

Hello

I wanted to draw other members to a seemingly inconsistent response from one www site in communicating with different Airvpn servers.

A studnt who uses Airvpn (and I have confirmed this) discovered that some web sites, when connected through some Airvpn servers returns a <<Server not found>>  or a <<DNS server could not be found>> error.

Yes, when a different Airvpn server is selected, the site connects with no issues.

The site is ctc.usma.edu.

Two browsers were used: firefox and opera. Both are the latest versions. And various blockers etc were all turned off. O/S is Debian Jessie.

It seems not to be a dreaded 5-eyes thing - the UK servers did not work. But one Swiss server did and another did not.

I was wondering if any other reader have encountered this, and also if any folks have an explanation.

Thanks heaps for your time and for reading.

 

Here are the results:

 

Airvpn - Sweden
Firefox - no
Opera - no

 

When using the "VPN" built into opera (yes, I know it is not a real vpn), and selecting a US server:

Opera/VPN US - Yes
Opera/VPN CAN - yes

As an aside, when the opera exit was in the US,  ipleak.net revealed 68 DNS servers!

Netherlands
Firefox - no
Opera - no

UK - Nashira
Firefox - no
Opera - no

US - Sabik
Firefox - Yes
Opera - Yes

US - Pavanos
Firefox - Yes
Opera - Yes

Switzerland - Virginis
Firefox - Yes
Opera - Yes

Katalpha
Firefox - no
Opera - no