MediaWiki internal error.

Original exception: [ZgX99sjwfHO0zmUjKOFTfAAAAJU] /data/Talk:Toban_Saroyan/history MWUnknownContentModelException: The content model 'flow-board' is not registered on this wiki.
See https://www.mediawiki.org/wiki/Content_handlers to find out which extensions handle this content model.
Backtrace:
from /var/www/vhosts/buckwiki.com/httpdocs/w/includes/content/ContentHandlerFactory.php(203)
#0 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/content/ContentHandlerFactory.php(273): MediaWiki\Content\ContentHandlerFactory->validateContentHandler()
#1 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/content/ContentHandlerFactory.php(191): MediaWiki\Content\ContentHandlerFactory->createContentHandlerFromHook()
#2 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/content/ContentHandlerFactory.php(97): MediaWiki\Content\ContentHandlerFactory->createForModelID()
#3 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/page/WikiPage.php(311): MediaWiki\Content\ContentHandlerFactory->getContentHandler()
#4 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/MediaWiki.php(448): WikiPage->getContentHandler()
#5 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/MediaWiki.php(331): MediaWiki->initializeArticle()
#6 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/MediaWiki.php(923): MediaWiki->performRequest()
#7 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/MediaWiki.php(576): MediaWiki->main()
#8 /var/www/vhosts/buckwiki.com/httpdocs/w/index.php(50): MediaWiki->run()
#9 /var/www/vhosts/buckwiki.com/httpdocs/w/index.php(46): wfIndexMain()
#10 {main}

Exception caught inside exception handler: [ZgX99sjwfHO0zmUjKOFTfAAAAJU] /data/Talk:Toban_Saroyan/history MWUnknownContentModelException: The content model 'flow-board' is not registered on this wiki.
See https://www.mediawiki.org/wiki/Content_handlers to find out which extensions handle this content model.
Backtrace:
from /var/www/vhosts/buckwiki.com/httpdocs/w/includes/content/ContentHandlerFactory.php(203)
#0 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/content/ContentHandlerFactory.php(273): MediaWiki\Content\ContentHandlerFactory->validateContentHandler()
#1 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/content/ContentHandlerFactory.php(191): MediaWiki\Content\ContentHandlerFactory->createContentHandlerFromHook()
#2 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/content/ContentHandlerFactory.php(97): MediaWiki\Content\ContentHandlerFactory->createForModelID()
#3 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/page/WikiPage.php(311): MediaWiki\Content\ContentHandlerFactory->getContentHandler()
#4 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/page/WikiPage.php(297): WikiPage->getContentHandler()
#5 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/page/Article.php(2112): WikiPage->getActionOverrides()
#6 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/actions/ActionFactory.php(270): Article->getActionOverrides()
#7 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/actions/ActionFactory.php(372): MediaWiki\Actions\ActionFactory->getAction()
#8 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/context/RequestContext.php(291): MediaWiki\Actions\ActionFactory->getActionName()
#9 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/context/ContextSource.php(130): RequestContext->getActionName()
#10 /var/www/vhosts/buckwiki.com/httpdocs/w/extensions/CharInsert/includes/Hooks.php(12): ContextSource->getActionName()
#11 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/HookContainer/HookContainer.php(160): MediaWiki\Extension\CharInsert\Hooks->onBeforePageDisplay()
#12 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/HookContainer/HookRunner.php(939): MediaWiki\HookContainer\HookContainer->run()
#13 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/OutputPage.php(2894): MediaWiki\HookContainer\HookRunner->onBeforePageDisplay()
#14 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/exception/MWException.php(184): OutputPage->output()
#15 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/exception/MWException.php(218): MWException->reportHTML()
#16 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/exception/MWExceptionHandler.php(130): MWException->report()
#17 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/exception/MWExceptionHandler.php(249): MWExceptionHandler::report()
#18 /var/www/vhosts/buckwiki.com/httpdocs/w/includes/MediaWiki.php(595): MWExceptionHandler::handleException()
#19 /var/www/vhosts/buckwiki.com/httpdocs/w/index.php(50): MediaWiki->run()
#20 /var/www/vhosts/buckwiki.com/httpdocs/w/index.php(46): wfIndexMain()
#21 {main}