Have you replaced the original WiFi card with something else? I cannot tell by what you wrote in your post.

Do you have a software firewall running on your laptop? If so, try disabling it temporarily to see if that makes a difference.

Many users report Killer cards blocking access to certain web sites. IIRC, some settings needed to be changed. Open Killer Control Center or Killer Network Manager | Settings: disable Killer Prioritization Engine. Under System Settings: disable Advanced Stream Detect.

If that doesn't make a difference, disable other Killer enhancements.

A Dell Community Manager added this: Device Manager | View | Show hidden devices | Expand Network adapters | Right-click Microsoft WiFi Direct Virtual Adapter | Disable device

I read that Dell SmartByte can slow WiFi and cause other issues. Some forum people recommend to disable/uninstall it. JOcean posted this: You may have Smartbyte installed and running. This web page https://windowsreport.com/smartbyte-services/ at Windows Report explains how to uninstall and make sure it does not come back through SA [SupportAssist]

See this-- FAQs - eduroam.org

Unfortunately, the configuration tool linked in that page is not suited for my organizations.

No, I did not.

I have made / repeated all the tests you suggested, with no success.

But, is there any place in the system where the reason of the connection failure is written? I had problems with setting up the VPN and I was able to solve them by looking at the log messages in the Even Viewer. Why are there no traces of the WiFi connection attempts?

It sounds weird, but going into device manager and totally deleting/uninstalling the WiFi card driver and letting it reinstall has fixed issues in the past. It sounds like you want to reset something to do with this WiFi card (considering only one network is effected).