No page access since 10 days to: https://commons.wikimedia.org/wiki/Category:SVG_logos_of_the_United_Kingdom !?
But **only if logged in** (probably due the default English language, see below), testet with Firefox (give 503) and Chrome (give 500) on two different machines (Win7).
```
Request from xx.xx.xxx.xx via cp3042 cp3042, Varnish XID 867253101
Error: 503, Service Unavailable at Sat, 22 Jul 2017 21:38:12 GMT
```
So this is probably a gadget error or similar user setting.
Edit: Some people reported a relation with the language setting:
https://commons.wikimedia.org/w/index.php?title=Commons:Help_desk&oldid=251473271#Commons_categories_not_available_-_Kategorien_nicht_aufrufbar.
So this server error only appears on **non English** language setting.
**Workaround ** is to switch to EN (clear cache and switch back to the user language).