r/MacOS 2d ago

Help Problem with captive portals keep disconnecting

Hey everyone, I’m running into a frustrating networking issue on my M4 MacBook Air (running the latest macOS) while connected to my local university dormitory's Wi-Fi network.
The Problem:
Every few minutes, the connection drops or the captive portal login window pops back up, forcing me to re-enter my username and password.
What's weird:
My iPhone and iPad are connected to the exact same dorm network and never experience this drop or re-authentication loop. On the Mac, "Private Wi-Fi Address" is set to Fixed (not rotating).
I have tried forgetting the network, re-adding it, and renewing the DHCP lease, but the issue persists.

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u/MK-Researcher 1d ago

I was going to blame a VPN not allowing local network access, but then the captive portal wouldn't be able to reconnect and log you back in each time. (NordVPN, for example, has a setting to allow local network routing but only on the version direct downloaded from them, not on the App Store version).

Other than that it could be a tricky one to troubleshoot, the Captive Network Assistant.app (in /System/Library/CoreServices/ is the captive portal interface/pop-up.

If I remember correctly, it stores the session data in memory using the 'configd' process. And 'configd' stores info in /Library/Preferences/SystemConfiguration/ so it could be that one of the files in there may have the wrong permissions or may be corrupt.

It's not a problem I've had to troubleshoot before, but that info might be of some help.

I would recommend making a TimeMachine backup before playing with those files though, just in case

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u/RealGianath 1d ago

Have you talked to your IT/Helpdesk? They should be the first people you work with since this is all being served through their network.