Hi,
As a computer science student i have a bit of experience with IT and even though my knowledge of Computer Networking is pretty basic i tried to systematically narrow down on the Error. Now since i'm new here i can't post all the links i would want to post. So if anyone wants a Link to one of the sites i used to look at it themselves just send me a PN and ask:
First i used a website that tries to access a site from different Locations to see if they can confirm that the problem is localized. While its perfectly normal to have a few tests fail, out of 43 Locations 8 failed when i last checked. Including all 4 German loacations and both french locations. That is not normal. (Just ignore the second Frankfurt, it appears some times and others it doesn't)
Theory 1: Its Browser related
I tested the following Browsers:
Chrome (private & normal), Firefox (private & normal), Internet Explorer, Opera* and Safari.
*Opera was the only one that worked, but ONLY IF the VPN was active.
Theory 2: Its Device related
I tested on my Windows 7 PC (all Browsers), an Ubuntu VM (only Firefox) and ios (Safari and Firefox). It only worked on Win7 with Opera WITH a VPN.
Theory 3: DNS Error
On Chrome i got the following Error: ERR_NAME_RESOLUTION_FAILED and on Opera (without VPN): DNS_PROBE_FINISHED_NXDOMAIN And if you look at the reason for the failed Tests in the Screenshot you can see that they state a DNS Lookup Error.
These errors all point towards a problem with the DNS. If you don't know what this is, you can imagine it as the phone book of the internet. In order to access a website your computer neeeds the IP Adress of the Server. But since they are difficult to remember we use an address that is easy to remember for us humans. For example: Google.com will be converted to 216.58.208.46 by the DNS Server. (If you type that IP in your browser, you should end up on Google, just as you would if you had typed in Google.com)
If an IP changes it can take some time until all DNS Servers have registered this change. But usually this doesn't take more then 24 hours and the error has persisted for at least 60 hours at this point.
Anyways, i tried the usual troubleshooting steps for such an error, like flushing the DNS Cache and so on, but this also didn't help. Then i tried using different DNS Servers. Neither the default by my ISP, the on by Google nor the one by Cloudflare worked. Now my VPN uses a cached Google DNS, so i would have assumed that at least the Google one should have worked. But it didn't.
Theory 4: ISP- or Geoblocking
Since the problem seems to be focused on Germany and France and a VPN solves the problem, Geoblocking comes to mind. Now why would a forum on papermodeling ban two countries? It makes no sense. The same goes for ISP blocks (These are usually done because the government orders them to block certain sites). I find it unlikely that multiple german and french ISPs would simultaneously ban a forum like this. (I'm using a local ISP with their own local infrastructure, so i know that the other people that have problems will have different ISPs.)
Now why would ISPs block a paper modeling forum? Well I thought that maybe one of the 22 other websites that are hosted on the same server (Which then also have the same IP Adress as the forum. This also means that if you type the Forums IP into your browser you won't get to the forum unlike the example with google.) was supposed to be blocked and someone screwed up and the other sites are just collateral damage. How do i know there are 22 other sites on this Server? Its actually quite easy: First i looked up the IP of the forum (its 144.208.108.102 for anyone curios). This already showed me that there are 22 other sites hosted at this IP but not what they are. To find that out i then did a reverse lookup of the IP. And when i saw the list one site immediately cought my eye and i thought: "This must be it! This sounds like something that should be blocked!" But sadly (or rather luckily! Depends on the Point of View) this wasn't the case. Since i could access a few of the Sites without an VPN i knew my hypothesis was wrong. So i decided to look at the website in spite of the name and it turned out to be by a researcher who looks into how domestic violence affects children and apparently didn't think that her Sitename might be misunderstood for a VERY different kind of site (I was very glad that it wasn't what i orignially thought it was when i clicked that link! Maybe i'm also the only one who thinks this way and the internet has just ruined me). It was also one of the sites that worked in Germany without a VPN. In the end i could access just 7 without an VPN and 21 with an VPN (The remaining 2 Sites only returned a fairly generic HTTP Error).
Conclusion:
Since the Issue happens on multiple Devices with multiple Browsers its safe to assume that they are not the culprit.
A DNS Error would be possible but while it perfectly fits some of my observations, others don't fit at all. (Its Schrödingers DNS Error
) The good news is that it should clear up eventually if this is the case.
All in all i would say that my Evidence points more towards some kind of block. Either intentionally or by accident. If a government blocks a website they often do this on a very basic level which can be circumvented easily using a VPN. But its odd that this apparently started simultaneously in France and Germany. Also in 2014 Hackers leaked a list of blocked Sites. It was mostly stuff that is clearly illegal, even by the URL. Stuff that usually gets hosted in small countries with lax laws, not the US or Europe. The site mentioned would fit on that list - but only by name. Also it was one of the few that actually was accessible and all others looked and sounded fine. So this theory is out.
This would leave a geoblock. A Geoblock would fit all evidence. But why? It can't be because of GDPR non-compliance since it is available in other european countries.
Since most of the sites on that server are broken in Germany, my best bet is a broken or at least wonky configuration by the Hosting Provider. So i do think, that the Forum Admins should contact the Hoster if this doesn't clear up in a couple of days by itself. Maybe if it's still broken on Monday, then it will have been ~1 Week.
So all in all: It doesn't really makes much sense to me. But my best guess is probably a DNS Error or some wrong configuration by the Hosting Provider.
Sadly the only thing i can advise atm. is to just wait and hope that it resolves itself and to use a VPN in the meantime.
Johannes