Internet connectivity problems after playing with Firewall - even after turning off Firewall

I tried experimenting with my Macbook's Firewall and tried turning Firewall on for one application. Since then I've had persistent problems with connecting to the internet. This is even after turning off Firewall and erasing any changes that I made to it.


I have turned off and back on my MacBook as well as my browser multiple times. The error message is consistent between browsers: on Firefox it's pr_end_of_file_error no matter what website I'm connecting to. I don't use a VPN or a proxy, and since the problem has surfaced I've been trying to fiddle with proxy settings (as was suggested by people troubleshooting based on the error message) without success.


I'm on Mac OS 11.2.3, Macbook Air M1 2020. The version of Firefox that I'm using is 89.0. I'm unable to upgrade either because I can't access internet.


WiFi shows me connected to the internet and gives me an IP address.


I'm normally quite savvy with computers but this has me stumped. Any help is appreciated!

Posted on Jun 16, 2021 9:30 AM

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Posted on Jun 25, 2021 1:20 AM

Solved: resetting NVRAM corrected the problem in all browsers. What a relief!

6 replies

Jun 16, 2021 6:34 PM in response to jivril

The obvious question to ask is if the problem also manifests in Safari. If Safari works normally while Firefox does not, consider resetting Firefox to defaults: https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings


If the problem continues with Safari, here are some additional steps you can take but most apply only to it.



If you don't get anywhere, you can use the following procedure to determine if the problem is internal or external to your Mac. Causes may involve your router, your ISP, the DNS Server(s) it uses, or certain user-configurable options.


  1. Shut down your Mac.
  2. Start your Mac using macOS Recovery
  3. Launch Safari from Recovery mode. It will lack your bookmarks, favorites, history and other preferences.


Determine if the problem persists while using Safari in that mode. After that, restart your Mac normally, and reply with your observations.

Jun 17, 2021 8:26 AM in response to jivril

In that case, the problem lies beyond your Mac, so reverting it to factory defaults won't fix it.


Running Safari in Recovery mode bypasses any changes you may have made to network settings or the macOS application firewall. Reset your router instead. If it doesn't help, the next step would be to contact your ISP or find a way to temporarily use a different one. You can use an iPhone's "personal hotspot" for example.

Jun 17, 2021 8:49 AM in response to jivril

I agree it doesn't make sense, but neither does erasing your Mac and reverting to factory settings. I doubt it will accomplish anything but I'm at a loss to suggest anything else. What's worse is that if it works we will never know the cause, which means it's certain to happen again.


When things don't make sense it means both you and I are working with incomplete information.


jivril wrote:

I'm on Mac OS 11.2.3, ...


... which is very outdated. If you can't update macOS even in Recovery mode it's kind of a show-stopper though.

Jun 17, 2021 7:27 AM in response to John Galt

Thank you for replying!


As I mentioned in my post, the error is not tied to any specific browser. When I started Safari in recovery mode, I got the same error of not being able to connect to the website due to unsafe connection.


After turning on my MacBook again after recovery mode there is no change.


It sure seems like my next step will have to be returning my computer to factory settings. I'd be happy to try anything else before that if you had any ideas. Cheers!

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Internet connectivity problems after playing with Firewall - even after turning off Firewall

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