If you are trying to download mods from Nexus Mods using the Vortex Mod Manager, but keep getting authentication or authorisation errors that prevent any of your downloads from starting. This article will walk you through quite a few different things you'll need to try in order to solve this problem, though thankfully, they are all pretty quick and easy.

Takeaways:

  1. Learn how to fix mods not downloading in Vortex Mods because of Login Authentication and Authorisation errors.
  2. Mods won't download in Vortex Mod Manager because of authentication errors.

What is an Authentication Error in Vortex Mod Manager?

An authentication error usually means Vortex is having trouble verifying your account credentials or connecting to the mod hosting site (like Nexus Mods). This can block mod downloads. Usually, it happens if you turn on a VPN, Proxy or if you haven't signed in for a while. Vortex Mod Manager will force sign you out and break the connection to Nexus Mods.

How to Fix Mods Not Downloading in Vortex Mod Manager | Authentication/Authorisation Errors

  • Open Vortex and go to the "Accounts" tab.
  • Make sure you are logged into your Nexus Mods account. (It has to be the same account on both)
  • If you see you’re logged out or if the login appears broken, try logging out and logging back in.
  • Use the "Login with Nexus Mods" button to refresh your session.

Note: If it still doesn't work, sign out of Vortex Mods manually and the website manually. Then sign in to Nexus Mods first. If that still doesn't work, clear your browser cache before trying again.

Update Vortex to the Latest Version

Authentication issues can sometimes be caused by outdated software. They can also trigger the sign out event that causes the problem as well.

  • Go to Help > Check for Updates and install any available updates.
  • Restart Vortex after updating.
  • Then make sure you are actually signed in.
  • If you aren't signed in, it won't work.

Clear Vortex Mods Cache & Browser Cache

There's a solid chance it's a caching issue, so clear your browser cache and the mod manager cache.

  • Go to Settings > Downloads and look for an option to clear cache.
  • Alternatively, clear the Vortex cache manually:
  • Close Vortex.
  • Go to: %AppData%\Vortex\cache (on Windows).
  • Delete the contents of the cache folder.
  • Restart Vortex and try downloading again.

How to Fix Mods Not Downloading in Vortex Mod Manager Authentication Authorisation Errors

Check Your Internet Connection and Firewall

  • Make sure your internet is stable.
  • Verify your firewall or antivirus isn’t blocking Vortex.
  • Add Vortex as an exception in your firewall/antivirus settings.
  • Temporarily disable antivirus/firewall to test if it fixes the issue (remember to re-enable afterwards).

Reauthorise Nexus Mods API Key (If Applicable)

Some mods or features require an API key. Most people won't be using an API key. If you need to, you will know about it.

  • Go to your Nexus Mods account profile and generate a new API key.
  • In Vortex, go to Settings > Accounts, and input the new API key.
  • This helps Vortex authenticate correctly.

Reinstall Vortex

This is pretty straightforward. Just uninstall Vortex and install it again. Depending on how you store mods, be prepared to redownload them all again.