Dunedan

The symptoms are the same as here: Even though I went back and forth with the user there in private messages, we weren't able to figure out the cause. At least we managed to narrow it down to the specific PC, so something is somehow wrong with the Windows installation. It'd be interesting here as well to get answers to the questions I posted here:

You can be glad you don't see the amount of spam they're trying to post.

The account "tata12" is not registered. So if you tried to log in with that user account, that's probably the reason why it's not working, even though you should get a different error message in that case.

Ok, this is a different problem then.

As per the Terms of Use of the multiplayer lobby registering multiple accounts is prohibited. Please contact me via private message so we can sort out which of these two accounts to delete again.

That's definitely interesting and the first time somebody reported this problem. Can you please send me a private message with the lobby username of your friend so I can have a look if we got something in the logs for these connection attempts?

What's the version of 0ad she's using? Are you 100% sure it's r28? Can you confirm that it worked with the same internet connection before? What's the name of the internet service provider? If you can test, does it work when using another internet service provider? When running "certmgr.msc" and selecting "Trusted Root Certification Authorities" -> "Certificates" in the left pane, does the list of certificates contain one or more containing "ISRG"?

You probably disabled TLS encrypted connections to the multiplayer lobby in the past. See:

And for completeness sake here is the announcement post the banner links to (for everybody who stumbles over this thread after the banner is gone):

The overall Terms of Use forbid harmful and threatening behavior. This of course applies to game names as well. We've taken care about that specific case in the meantime.

Unencrypted connections to the multiplayer lobby are now not possible anymore.

When you connect to the multiplayer lobby, 0ad uses a secure, TLS-encrypted connection by default. However, up to now we also offered the ability for players to disable that encryption. This won't be possible from some time tomorrow (2026-03-06) on anymore, as we want to improve the security and privacy of our players. For the past two weeks, every player who disabled TLS-encryption in the past, and therefore connected to the multiplayer lobby with an unencrypted connection, received a notification to change their configuration to enable it. If you haven't followed these instructions or just haven't connected to the multiplayer lobby since then, here is what you have to do to continue to be able to connect to the multiplayer lobby: From the main screen of the game, navigate to "Settings" → "Options" → "Networking / Lobby" and enable "TLS encryption" there. As an alternative you can also locate your 0ad configuration file and change lobby.tls = "false" to lobby.tls = "true" there.

Don't keep your hope up too much.

Would make sense if they would though, wouldn't it?