Error 0 - Forbidden

[PactCommander]

I'm experiencing the same problem.
Last evening it worked just fine, I even ran a Windows 11 update right before I logged into FF14. Played for a bit and logged off just fine, no warning, no issues back then.
Now I want to log back in on my laptop and I get the same notification as you all do.
Funny thing is, I could log into my account on my sister PCs. We go online via the same router so I doubt it has something to do with the internet connection when I can log in on her PC without any problems.

[PactCommander]

Update on my problem

I'm not sure if this is a permanent solution but at least it let me log in again.
I deleted all browser history from my Microsoft Edge browser, since I think FFXIV's launcher uses this browser. Also I went to "Settings" in Microsoft Edge, then "System and Performance" -> "System" and toggled "Use graphics acceleration when available" option off (since it was on on my laptop) and back on, followed by restarting the browser to apply the changes.

After that I was able to log into FF XIV again without any problems.
I'm not sure if the graphic acceleration thing is necessary to do or if this is just a coincidence.
Also no guarantee these steps will help everyone here, but it won't hurt trying either Just wanted to say, this might be a solution for some.

[Thefinal]

So I contacted technical support and they gave me a fix, and it worked! YMMV, and what worked for me might not work for you. Posting the info here:

Thank you for your patience while we thoroughly investigate your concern and for the information provided. We would like for you to please open the system browser and follow the steps below:

[Windows 10/11 using Microsoft Edge]

To access Internet Explorer, please use the following steps below:

1.) Go to “Control Panel” .
2.) Go to “Internet Options” then “Programs”, then click “Manage add-ons”.
3.) Click "Learn more about toolbars and extensions" at the bottom and this will launch Internet Explorer once more for Windows 11.
4.) Once you have launched Internet Explorer, please click the gear icon in the top right-hand corner.

- Click "Internet Options".
- Under the "General" tab, please delete ALL browser history.
- Under the "Security" tab, please move the slider to the lowest possible settings or no higher than "Medium".
- Under the "Privacy" tab, click "Advanced" and select "Accept" under both First Party and Third Party Cookies.
- Under the "Advanced" tab, please make sure that "Allow software to run or install even if signature is invalid" is CHECKED.
- Make sure that all SSL and TLS (EXCEPT SSL 3.0) are CHECKED. [SSL 3.0 should be UNCHECKED]
- Hit "Apply" to save the settings , and then "OK", to close the Internet Options menu.
- Right-Click on the FFXIV launcher icon and select "Properties".
- Hit "Apply", then click "OK" to save the changes.

After the save, restart the PC. Once your PC has been restarted, right-click the FFXIV launcher icon once more and select "Run as Administrator".

[Windows 10/11 using Internet Explorer]

- Once you have launched Internet Explorer, please click the gear icon in the top right-hand corner.
- Click "Internet Options".
- Under the "General" tab, please delete ALL browser history.
- Under the "Security" tab, please move the slider to the lowest possible settings or no high than "Medium".
- Under the "Privacy" tab, click "Advanced" and select "Accept" under both First Party and Third Party Cookies.
- Under the "Advanced" tab, please make sure that "Allow software to run or install even if signature is invalid" is CHECKED.
- Make sure that all SSL and TLS (EXCEPT SSL 3.0) are CHECKED. [SSL 3.0 should be UNCHECKED]
- Hit "Apply" to save the settings , and then "OK", to close the Internet Options menu.
- Right-Click on the FFXIV launcher icon and select "Properties".
- Hit "Apply", then click "OK" to save the changes.

After the save, restart the PC. Once your PC has been restarted, right-click the FFXIV launcher icon once more and select "Run as Administrator".

We hope this will prove useful in resolving the issue that you are experiencing. If the error persists after trying the aforementioned troubleshooting suggestions, please feel free to reply back and the team will be more than happy to investigate further into your concern.

[Chigs]

I tried to follow this but my Windows 11 machine had nothing in relation to Internet Explorer so I decided to just delete the cache etc from Edge and that seems to have worked.