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"?
I don't think I got like any upgrades for them, so that would make sense. Should I start a forum in the art forum section to see if anybody would want to help?