Hi This was a common problem
Windows 11 needs to Run As Administrator to install UEFN updates
Works fine on Windows 10, but Windows 11 Enhanced Security needs “Run As Administrator”
There may problem may be running Opera.
Try Microsoft Edge and Google Chrome to initially log in and join your Epic account with Fortnite and installation then you can go back to Opera but we have seen problems where VPN had to be used with browsers other than Chrome and derivatives.
UPDATE - 23-jan25 loaded Opera on Win 11 and tried as you described.
So here are the features that are different from Google Chrome
Free VPN: Protects your privacy by securing your internet traffic
Epic does NOT support configured VPN by Opera you must conform to Epic internet settings.
Win11 will NOT allow Opera to configure the Windows firewall and does not recognise the cached cookie and your firewall.
Unreal Engine must have Chrome on Explorer and you MUST set Chrome as your default browser to allow login to Epic UEFN servers installation.
You need to find Opera setup manual and manually configure the VPN, EPIC does not support
Built-in ad blocker: Blocks ads and popups, which can improve page loading times and protect against malvertising
The authentication page is a popup and Opera is blocking this
Protection against trackers: Protects against tracking scripts on websites
Well login is a website script so that’s blocked EPIC as well.
In Summary only Google Chrome must be your default browser of MS Edge ( based on Chrome)
The Client Windows firewall is not correctly set up.
The problem lies with your PC not being configured to support EPGL and hence Fortnite
Its not a bug its client PC incorrectly set up