Use the correct endpoint for this - hosted by a CDN and therefore capable of handling much greater volumes of traffic.

CCMAIL: plasma-devel@kde.org
CCMAIL: distributions@kde.org

kcms/kfontinst/kcmfontinst/kfontinst.knsrc

@@ -41,7 +41,7 @@ Name[vi]=Phông chữ
 Name[x-test]=xxFontsxx
 Name[zh_CN]=字体
 
-ProvidersUrl=https://distribute.kde.org/khotnewstuff/fonts-providers.xml
+ProvidersUrl=https://cdn.kde.org/khotnewstuff/v1/fonts-providers.xml
 Categories=KDE-Look.org Fonts
 TargetDir=kfontinst
 Uncompress=archive