Hi,
It happens when a new java version is released, or windows is updated and the pc has to be restarted. I disable every option for the firewall (domain network, private network, and public network goes off) and the project opens normally. Then I restore the firewall settings and unity can open other projects again.
(Using unity 2017.3.0f3 64 bit on a Windows 10 Home computer)

Same with Unity Unity 2018.2.0b1 (64-bit).
Setting up noproxy from UNITY_NOPROXY environment variable. Setting to: 127.0.0.1,localhost

In Unity 2017.3.0f3 Same.
Dont connect to Store, Services, none.

Same with Unity 2017.3.0f2(64bit),This is a big problem,I can not get it to work by any other means

Sameeee.... :/

Same with Unity 2017.3.0f2

Same problem with 2017.2.0f3. It would freeze Unity Editor and force me to close the editor.

This is a huge issue for our studio as we don't have internet connections due to MPAA restrictions.

I found a strange way of getting it work. When unity gets stuck on loading bar I turn off my internet, it gives me an option of working offline I click that. Unity stucks again, then I close unity and launch it again and this time it worked fine. But I have to repeat this process everytime because on next launch it brings me back to the original problem.

Hello, please fix this issue. Since yesterday (04/10/2017), we could not open any projects, even create new one is always (not responding). We have to manually kill the session. We are in Unity3D 2017 1.1.f1 in MacOS Sierra 10.12.6. The only solution we found is: disable network. then open unity without any probleme. Once here's the internet connection, we could not open Unity3D anymore. Please fix is. It seems some issue on this server ? ( https://public-cdn.cloud.unity3d.com/config/production) Please take a look at these log files:

[with internet connect, failed to open]
COMMAND LINE ARGUMENTS:
/Applications/Unity/Unity.app/Contents/MacOS/Unity
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[CEF] undefined in file:///%2FUsers%2FAdmin%2FLibrary%2FUnity%2FPackages%2Fnode_modules%2Funity-editor-home%2Fdist/assets/unity-editor-home.js at line 39
2017-10-05 11:01:45.630 Unity Helper[6342:76795] XType: failed to connect - Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named com.apple.fonts was invalidated." UserInfo={NSDebugDescription=The connection to service named com.apple.fonts was invalidated.}
2017-10-05 11:01:45.630 Unity Helper[6342:76795] Font server protocol version mismatch (expected:5 got:0), falling back to local fonts
2017-10-05 11:01:45.630 Unity Helper[6342:76795] XType: unable to make a connection to the font daemon!
2017-10-05 11:01:45.630 Unity Helper[6342:76795] registering /System/Library/Fonts/*, /System/Library/Fonts/Base/*, and /Library/Fonts/* locally
IsTimeToCheckForNewEditor: Update time 1507193961 current 1507194107
/Users/Admin/Desktop/Unity3D Projects/RHEnvi
Loading GUID <-> Path mappings...0.000034 seconds
Loading Asset Database...0.005305 seconds
Audio: FMOD Profiler initialized on port 54900
AssetDatabase consistency checks...0.023443 seconds
Refreshing native plugins compatible for Editor in 1.61 ms, found 0 plugins.
Preloading 0 native plugins for Editor in 0.00 ms.
Initialize engine version: 2017.1.1f1 (5d30cf096e79)
GfxDevice: creating device client; threaded=1
Metal: Editor support disabled, skipping device initialization

[without internet connection, no problem!]
COMMAND LINE ARGUMENTS:
/Applications/Unity/Unity.app/Contents/MacOS/Unity
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
[warn] kq_init: detected broken kqueue; not using.: Undefined error: 0
Request timed out while processing request "https://public-cdn.cloud.unity3d.com/config/production", HTTP error code 0
.[UnityConnect] Request timed out.
[CEF] undefined in file:///%2FUsers%2FAdmin%2FLibrary%2FUnity%2FPackages%2Fnode_modules%2Funity-editor-home%2Fdist/assets/unity-editor-home.js at line 39
2017-10-05 11:04:40.095 Unity Helper[6421:78612] XType: failed to connect - Error Domain=NSCocoaErrorDomain Code=4099 "The connection to service named com.apple.fonts was invalidated." UserInfo={NSDebugDescription=The connection to service named com.apple.fonts was invalidated.}
2017-10-05 11:04:40.095 Unity Helper[6421:78612] Font server protocol version mismatch (expected:5 got:0), falling back to local fonts
2017-10-05 11:04:40.095 Unity Helper[6421:78612] XType: unable to make a connection to the font daemon!
2017-10-05 11:04:40.095 Unity Helper[6421:78612] registering /System/Library/Fonts/*, /System/Library/Fonts/Base/*, and /Library/Fonts/* locally
IsTimeToCheckForNewEditor: Update time 1507193961 current 1507194284
/Users/Admin/Desktop/Unity3D Projects/RHEnvi
Loading GUID <-> Path mappings...0.000034 seconds
Loading Asset Database...0.006072 seconds
Audio: FMOD Profiler initialized on port 54900
AssetDatabase consistency checks...0.024006 seconds
Refreshing native plugins compatible for Editor in 1.71 ms, found 0 plugins.
Preloading 0 native plugins for Editor in 0.00 ms.
Initialize engine version: 2017.1.1f1 (5d30cf096e79)
GfxDevice: creating device client; threaded=1
Metal: Editor support disabled, skipping device initialization