In short: It is likely that Unity will detect your IP location and if it’s in China, the Unity Hub you are downloading is different from the “Global” version of Unity Hub.
Here is the story if you want to know how I found it out:
Recently since the Unity Hub has been released, I reported quite a few times in this forum about the bugs and design problems of Unity Hub(You can see the posts by clicking my profile). Basically, most of my problem reported are related to Unity Hub’s extremely slow response when it started: the hub will not login until a few minutes after the hub is open, same for the available versions list and your existed Unity installations and so on. And often it fails completely to fetch these data and shows something like “The server is currently not responsive”. I have reported these several times and interestingly not a single Unity staff in the forum replied any of my post. Today when I tried to install the latest Unity 2019.2.9, the Hub fails to install again and shows that it cannot connect to the server despite I have a reasonably fast (500Mbps) internet connection. Then I realized that I have my VPN turned on which is connected from a US server (I am a developer located in China), and the problems I encountered previously may also happen to be when the VPN is on. So I turned the VPN off, and restarted the Hub. And as expected: everything loads instantly! Amazing, isn’t it?
Except it should be about the same speed if not faster with the VPN on, rather failed to connect at all. Can those seemingly “buggy” delays are because of my VPN? I didn’t turned my VPN on back when I downloaded the Hub, is it possible that my version Unity Hub only tries to connect Unity servers from China? With these questions, I made sure my VPN is on (so my IP location is in the US) and downloaded the Unity Hub again and overwrote my existed Unity Hub.
Now the magic happened again: the new Unity Hub downloaded connected everything almost instantly, no matter the VPN is on of off - it is ready to use the moment it launches! Wait a minute, there is also something different in the available Unity version list - in the previous copy of Unity Hub I installed, there are Unity versions for China, but the new version doesn’t have those items (See the images below).
Previous copy:
New copy:
Now it is quite clear that if you are in China or your IP address is in China when you downloaded the Unity Hub, you may be very well using a “secret Chinese version” of Unity Hub rather than the “regular version”, despite the two versions have same version number. It is “secret” because Unity didn’t tell us about it and they look almost identical and functions the same except the China version will only connect to servers in China, which is almost unusable if your IP address are outside China, while the “regular” or “global” version of Unity Hub is usable even if you are in China. This is really annoying especially you are a developer located in China who wants to use a “regular” version of Unity Hub. And to be honest, this sneaky behavior from Unity is a discrimination against Unity users from China, which is definitely what I do not want to see.