Internal error

[bbdbbcb7e5a870da73815a7a] /nano/Sandbox:potencial UnexpectedValueException from line 489 of /usr/share/mediawiki/includes/libs/rdbms/loadbalancer/LoadBalancer.php: Invalid server index index #DB_SLAVE

Backtrace:

#0 /usr/share/mediawiki/includes/libs/rdbms/loadbalancer/LoadBalancer.php(902): Wikimedia\Rdbms\LoadBalancer->getConnectionIndex()
#1 /usr/share/mediawiki/includes/libs/rdbms/loadbalancer/LoadBalancer.php(1049): Wikimedia\Rdbms\LoadBalancer->getConnection()
#2 /usr/share/mediawiki/includes/GlobalFunctions.php(2463): Wikimedia\Rdbms\LoadBalancer->getMaintenanceConnectionRef()
#3 /usr/share/mediawiki-extensions/Math/MathRenderer.php(267): wfGetDB()
#4 /usr/share/mediawiki-extensions/Math/MathRenderer.php(602): MathRenderer->readFromDatabase()
#5 /usr/share/mediawiki-extensions/Math/MathTexvc.php(411): MathRenderer->isInDatabase()
#6 /usr/share/mediawiki-extensions/Math/MathTexvc.php(378): MathTexvc->isInDatabase()
#7 /usr/share/mediawiki-extensions/Math/MathTexvc.php(87): MathTexvc->readCache()
#8 /usr/share/mediawiki-extensions/Math/Math.hooks.php(224): MathTexvc->render()
#9 /usr/share/mediawiki-extensions/Math/Math.hooks.php(204): MathHooks::mathPostTagHook()
#10 /usr/share/mediawiki/includes/parser/Parser.php(3921): MathHooks::mathTagHook()
#11 /usr/share/mediawiki/includes/parser/PPFrame_Hash.php(340): Parser->extensionSubstitution()
#12 /usr/share/mediawiki/includes/parser/Parser.php(2886): PPFrame_Hash->expand()
#13 /usr/share/mediawiki/includes/parser/Parser.php(1557): Parser->replaceVariables()
#14 /usr/share/mediawiki/includes/parser/Parser.php(652): Parser->internalParse()
#15 /usr/share/mediawiki/includes/content/WikitextContent.php(374): Parser->parse()
#16 /usr/share/mediawiki/includes/content/AbstractContent.php(590): WikitextContent->fillParserOutput()
#17 /usr/share/mediawiki/includes/Revision/RenderedRevision.php(263): AbstractContent->getParserOutput()
#18 /usr/share/mediawiki/includes/Revision/RenderedRevision.php(235): MediaWiki\Revision\RenderedRevision->getSlotParserOutputUncached()
#19 /usr/share/mediawiki/includes/Revision/RevisionRenderer.php(215): MediaWiki\Revision\RenderedRevision->getSlotParserOutput()
#20 /usr/share/mediawiki/includes/Revision/RevisionRenderer.php(152): MediaWiki\Revision\RevisionRenderer->combineSlotOutput()
#21 [internal function]: MediaWiki\Revision\RevisionRenderer->MediaWiki\Revision\{closure}()
#22 /usr/share/mediawiki/includes/Revision/RenderedRevision.php(197): call_user_func()
#23 /usr/share/mediawiki/includes/poolcounter/PoolWorkArticleView.php(216): MediaWiki\Revision\RenderedRevision->getRevisionParserOutput()
#24 /usr/share/mediawiki/includes/poolcounter/PoolCounterWork.php(162): PoolWorkArticleView->doWork()
#25 /usr/share/mediawiki/includes/page/Article.php(810): PoolCounterWork->execute()
#26 /usr/share/mediawiki/includes/actions/ViewAction.php(80): Article->view()
#27 /usr/share/mediawiki/includes/MediaWiki.php(531): ViewAction->show()
#28 /usr/share/mediawiki/includes/MediaWiki.php(313): MediaWiki->performAction()
#29 /usr/share/mediawiki/includes/MediaWiki.php(947): MediaWiki->performRequest()
#30 /usr/share/mediawiki/includes/MediaWiki.php(547): MediaWiki->main()
#31 /usr/share/mediawiki/index.php(53): MediaWiki->run()
#32 /usr/share/mediawiki/index.php(46): wfIndexMain()
#33 {main}