Thanks for reporting this. Can you please provide the stacktrace details of that exception?

MediaWiki internal error.

Original exception: [WpkrFj56nW0Wr9EZUPgctwAAAHQ] /index.php?title=Main_Page&mobileaction=toggle_view_mobile RuntimeException from line 57 of /home/pontus/subcultures.wiki/en/extensions/MobileFrontend/includes/MobileFrontend.hooks.php: wgMFDefaultSkinClass is not setup correctly. It should point to the class name of a valid skin e.g. SkinMinerva, SkinVector
Backtrace:
#0 /home/pontus/subcultures.wiki/en/extensions/MobileFrontend/includes/MobileFrontend.hooks.php(126): MobileFrontendHooks::getDefaultMobileSkin(RequestContext, MobileContext)
#1 [internal function]: MobileFrontendHooks::onRequestContextCreateSkin(RequestContext, NULL)
#2 /home/pontus/subcultures.wiki/en/includes/Hooks.php(177): call_user_func_array(string, array)
#3 /home/pontus/subcultures.wiki/en/includes/Hooks.php(205): Hooks::callHook(string, string, array, NULL)
#4 /home/pontus/subcultures.wiki/en/includes/context/RequestContext.php(406): Hooks::run(string, array)
#5 /home/pontus/subcultures.wiki/en/includes/context/ContextSource.php(154): RequestContext->getSkin()
#6 /home/pontus/subcultures.wiki/en/includes/OutputPage.php(2402): ContextSource->getSkin()
#7 /home/pontus/subcultures.wiki/en/includes/MediaWiki.php(858): OutputPage->output(boolean)
#8 /home/pontus/subcultures.wiki/en/includes/MediaWiki.php(870): MediaWiki->{closure}()
#9 /home/pontus/subcultures.wiki/en/includes/MediaWiki.php(523): MediaWiki->main()
#10 /home/pontus/subcultures.wiki/en/index.php(43): MediaWiki->run()
#11 {main}

Exception caught inside exception handler: [WpkrFj56nW0Wr9EZUPgctwAAAHQ] /index.php?title=Main_Page&mobileaction=toggle_view_mobile RuntimeException from line 57 of /home/pontus/subcultures.wiki/en/extensions/MobileFrontend/includes/MobileFrontend.hooks.php: wgMFDefaultSkinClass is not setup correctly. It should point to the class name of a valid skin e.g. SkinMinerva, SkinVector
Backtrace:
#0 /home/pontus/subcultures.wiki/en/extensions/MobileFrontend/includes/MobileFrontend.hooks.php(126): MobileFrontendHooks::getDefaultMobileSkin(RequestContext, MobileContext)
#1 [internal function]: MobileFrontendHooks::onRequestContextCreateSkin(RequestContext, NULL)
#2 /home/pontus/subcultures.wiki/en/includes/Hooks.php(177): call_user_func_array(string, array)
#3 /home/pontus/subcultures.wiki/en/includes/Hooks.php(205): Hooks::callHook(string, string, array, NULL)
#4 /home/pontus/subcultures.wiki/en/includes/context/RequestContext.php(406): Hooks::run(string, array)
#5 /home/pontus/subcultures.wiki/en/includes/context/ContextSource.php(154): RequestContext->getSkin()
#6 /home/pontus/subcultures.wiki/en/includes/OutputPage.php(2402): ContextSource->getSkin()
#7 /home/pontus/subcultures.wiki/en/includes/exception/MWExceptionRenderer.php(135): OutputPage->output()
#8 /home/pontus/subcultures.wiki/en/includes/exception/MWExceptionRenderer.php(54): MWExceptionRenderer::reportHTML(RuntimeException)
#9 /home/pontus/subcultures.wiki/en/includes/exception/MWExceptionHandler.php(75): MWExceptionRenderer::output(RuntimeException, integer)
#10 /home/pontus/subcultures.wiki/en/includes/exception/MWExceptionHandler.php(130): MWExceptionHandler::report(RuntimeException)
#11 /home/pontus/subcultures.wiki/en/includes/MediaWiki.php(550): MWExceptionHandler::handleException(RuntimeException)
#12 /home/pontus/subcultures.wiki/en/index.php(43): MediaWiki->run()
#13 {main}