"error sending request for url ()" on Mac M4 Pro, macOS Sequoia 15.7.4 – cannot sync or login

Anki Syncing & AnkiWeb
1

Hi everyone,

I’m experiencing a persistent network error in Anki that prevents me from logging in and syncing. I’ve spent several hours troubleshooting without success and would really appreciate any help.

System info:

  • MacBook Pro M4 Pro
  • macOS Sequoia 15.7.4 (24G517)
  • Anki 25.09.2 (Qt6), build 3890e12c, Python 3.13.5, Qt 6.9.1, Chromium 122

The error:
Immediately after trying to log in or sync, I get:

“A network error occurred.
Error details: error sending request for url ()”

Note the URL is completely empty – just ().

What I have already tried:

  • Restarting Anki, restarting MacBook
  • Syncing on a different device, which works
  • Updating Anki to latest version
  • Updating macOS
  • Turning VPN on/off
  • Disabling and re-enabling WiFi
  • Deleting prefs21.db and letting Anki recreate it (multiple times)
  • Full uninstall and reinstall of Anki
  • Disabling all add-ons (Shift+launch)
  • Switching to Anki 24.06.3 Qt5 (Intel version via Rosetta 2) – same error, but with additional detail: “error trying to connect: The certificate was not trusted”
  • Uninstalling Cisco (had Cisco security software installed)
  • Fully uninstalling Cloudflare WARP (had to force-kill the root process via Terminal)
  • Checking for proxy settings via scutil --proxy – none found
  • Checking for Cisco network extensions in /Library/Extensions – none found

Important finding:
Running curl -v https://sync.ankiweb.net/hostKey in Terminal succeeds perfectly – SSL handshake completes, certificate is trusted, connection is established. So the network itself is fine. The problem seems to be that Anki is attempting a request with an empty URL internally before ever reaching AnkiWeb.

Current state:
Anki works locally (I can study cards), but login and sync are completely broken. My cards are safe locally.

Has anyone seen this before, especially on Macs running Sequoia? Any ideas what could cause Anki to attempt a request with an empty URL?

Thank you!

2

If that other device is connected to the same internet source, then that pretty well confirms it’s something on this device that is preventing the connection to AnkiWeb. If that other device is connected to a different internet source, then it’s more likely it’s your internet source.

Was syncing working at some point, and stopped working? Or has it never been working on this device?

Most of the things you tried weren’t going to be fruitful – the only thing that matters is whether your computer can find the servers – see: Error establishing a secure connection when syncing - Anki FAQs . You’re on the right track with VPN/security/proxy sorts of things, but it sounds like you haven’t found the right one yet. I know that “iCloud private relay” is one that sometimes gets overlooked because it’s not called a “VPN”.

I can see why you might think that, but this is a very standard error, and I wouldn’t read too much into the empty parentheses. You can see other recent posts – Search results for '"error sending request for url" order:latest' - Anki Forums – for more ideas to try and things to check.