Forum - Recent Activity error

When I'm going on Recent Activity, I'm just getting a large error message labelled "Internal error". This is the text it's showing me:

[XKAVP4KXSJUqhQ6Wxde0qAAAAEg] /Special:WikiActivity Error from line 193 of /home/bigcart1/public_html/extensions/WikiActivity/WikiActivity.php: Call to a member function getForum() on boolean

Backtrace:

1. 0 /home/bigcart1/public_html/extensions/WikiActivity/WikiActivity.php(76): WikiActivity->listForum(array)
2. 1 /home/bigcart1/public_html/includes/specialpage/SpecialPage.php(569): WikiActivity->execute(NULL)
3. 2 /home/bigcart1/public_html/includes/specialpage/SpecialPageFactory.php(568): SpecialPage->run(NULL)
4. 3 /home/bigcart1/public_html/includes/MediaWiki.php(288): MediaWiki\Special\SpecialPageFactory->executePath(Title, RequestContext)
5. 4 /home/bigcart1/public_html/includes/MediaWiki.php(860): MediaWiki->performRequest()
6. 5 /home/bigcart1/public_html/includes/MediaWiki.php(517): MediaWiki->main()
7. 6 /home/bigcart1/public_html/index.php(42): MediaWiki->run()
8. 7 {main}

If there is an issue here with the site and not with me, I hope, it can be fixed quickly.