Browser / Version: Firefox 77.0
Operating System: Windows 10
Tested Another Browser: Yes Chrome
Problem type: Something else
Description: Cannot Login With Firefox Nightly. Chrome works Fine
Steps to Reproduce:
Cannot Login With Firefox Nightly. Chrome works Fine. The page looks like its working but gives a connection timed out error.
View the screenshot

Browser Configuration
_From webcompat.com with 鉂わ笍_
Thanks for the report, I was able to reproduce the issue. After sign in I'm redirected to https://www.playstation.com/en-us/ but still not signed in.

Note:
Console:

Tested with:
Browser / Version: Firefox Nightly 77.0a1 (2020-05-03)
Operating System: Windows 10 Pro
Moving to Needsdiagnosis for further investigation.
FYI - Just to add my specific experience for troubleshooting. I get redirected like this:
1. Clicked Here:

2. Redirected to this site:

3. Finally the server times out:

Let me know if you need any additional.
Your input is great, I just have a different behavior, but the same problem - we can't sign in.
I have the same experience as @softvision-oana-arbuzov , after signing in redirected to https://www.playstation.com/en-us/ and not signed in.
We have https://bugzilla.mozilla.org/show_bug.cgi?id=1626696 and reached out to Sony regarding the issue
@s0m3f00l your issue looks different. Could you please check if setting network.cookie.sameSite.laxByDefault pref to false in about:config changes anything?
Current Output of network.cookie.sameSite.laxByDefault = True:

Changed to false:

Clicked here:

Redirected here:

Not sure why. I turned off all the filtering (I usually run ad blockers and surricata but disabled them and Ublock for this test) and the results are the same...
click here:

Password prompt and sign in:

Final Result and error:

I have tried with network.cookie.sameSite.laxByDefault both set to true and false (F76 on Win) but I get the same 'timed out' message either way. I've also tried clearing all cookies and storage before trying again. Is anyone seeing different results with this option?
Why was this closed @karlcow? Its not fixed in any of the duplicates you listed and both reference this ticket?
And this is still not fixed.
Regular Cleaning. The milestone was duplicate with an open status
The right bug to follow this issue is https://bugzilla.mozilla.org/show_bug.cgi?id=1626696
which is still open.
Let me read the full issue again.
So I tried just now with a clean new profile. no addons, no cache, just created for the test.
network.cookie.sameSite.laxByDefault set to false.