#### Error
If I call `https://www.wikidata.org/w/index.php?title=Q28966042&redirect=no` then I get a server error or an exception like `[Xi8HgwpAADsAADteSMgAAACA] 2020-01-27 15:53:39: Fataler Ausnahmefehler des Typs „Wikibase\DataModel\Services\Lookup\UnresolvedEntityRedirectException“`.
Wikimedia error message: "Error
Our servers are currently under maintenance or experiencing a technical problem. Please try again in a few minutes.
See the error message at the bottom of this page for more information."
```counterexample
2020-01-27 15:53:39 [Xi8HgwpAADsAADteSMgAAACA] mw1264 wikidatawiki 1.35.0-wmf.16 exception ERROR
Wikibase\DataModel\Services\Lookup\UnresolvedEntityRedirectException: Unresolved redirect from Q28966040 to Q28966039
at /srv/mediawiki/php-1.35.0-wmf.16/extensions/Wikibase/lib/includes/Store/RevisionBasedEntityLookup.php:75
```
```name=trace,lines=10
#0 /srv/mediawiki/php-1.35.0-wmf.16/extensions/Wikibase/lib/includes/Store/LatestRevisionIdResult.php(157): Wikibase\Lib\Store\RevisionBasedEntityLookup->Wikibase\Lib\Store\{closure}(integer, Wikibase\DataModel\Entity\ItemId)
#1 /srv/mediawiki/php-1.35.0-wmf.16/extensions/Wikibase/lib/includes/Store/RevisionBasedEntityLookup.php(77): Wikibase\Lib\Store\LatestRevisionIdResult->map()
#2 /srv/mediawiki/php-1.35.0-wmf.16/vendor/wikibase/data-model-services/src/Lookup/RedirectResolvingEntityLookup.php(72): Wikibase\Lib\Store\RevisionBasedEntityLookup->hasEntity(Wikibase\DataModel\Entity\ItemId)
#3 /srv/mediawiki/php-1.35.0-wmf.16/extensions/Wikibase/repo/RepoHooks.php(960): Wikibase\DataModel\Services\Lookup\RedirectResolvingEntityLookup->hasEntity(Wikibase\DataModel\Entity\ItemId)
#4 /srv/mediawiki/php-1.35.0-wmf.16/includes/Hooks.php(174): Wikibase\RepoHooks::onSkinTemplateBuildNavUrlsNavUrlsAfterPermalink(SkinVector, array, integer, integer)
#5 /srv/mediawiki/php-1.35.0-wmf.16/includes/Hooks.php(202): Hooks::callHook(string, array, array, NULL)
#6 /srv/mediawiki/php-1.35.0-wmf.16/includes/skins/SkinTemplate.php(1332): Hooks::run(string, array)
#7 /srv/mediawiki/php-1.35.0-wmf.16/includes/skins/SkinTemplate.php(455): SkinTemplate->buildNavUrls()
#8 /srv/mediawiki/php-1.35.0-wmf.16/includes/skins/SkinTemplate.php(217): SkinTemplate->prepareQuickTemplate()
#9 /srv/mediawiki/php-1.35.0-wmf.16/includes/OutputPage.php(2593): SkinTemplate->outputPage()
#10 /srv/mediawiki/php-1.35.0-wmf.16/includes/MediaWiki.php(974): OutputPage->output(boolean)
#11 /srv/mediawiki/php-1.35.0-wmf.16/includes/MediaWiki.php(987): MediaWiki->{closure}()
#12 /srv/mediawiki/php-1.35.0-wmf.16/includes/MediaWiki.php(530): MediaWiki->main()
#13 /srv/mediawiki/php-1.35.0-wmf.16/index.php(46): MediaWiki->run()
#14 /srv/mediawiki/w/index.php(3): require(string)
#15 {main}
```
#### Impact
* Users unable to read or edit part of the data.
* User stranded with no clue or further interface (useless system error).
* Raised MW exeption noise affecting (alerts and deploy abort).
* Raised HTTP 500 levels from prod traffic (alerts)
#### TODO
>>! In T243779#5865639, @Ladsgroup wrote:
> After talking to @Lydia_Pintscher her idea is that anything that's easiest to implement given that this page is barely going to be visited.