I have already updated all modules. I can still access Studio just fine. The frontend is not working. I will uncomment the code and see what errors may be revealed.

@LeonidS The problem was with MSolutions Instant Notify app. I set it to inactive and the frontend displayed without issue.

Here are the contents of the error message:

Fatal error: Uncaught Error: Class "BxNtfsTemplate" not found in /modules/msolutions/notify/classes/MsolutionsNotifyTemplate.php:16 Stack trace: #0 /inc/classes/BxDolModule.php(101): require_once() #1 /inc/classes/BxDolModule.php(60): BxDolModule->_initTemplate() #2 /modules/msolutions/notify/classes/MsolutionsNotifyModule.php(141): BxDolModule->__get() #3 /modules/msolutions/notify/classes/MsolutionsNotifyModule.php(710): MsolutionsNotifyModule->getCustomStyles() #4 /inc/classes/BxDolRequest.php(129): MsolutionsNotifyModule->serviceInjectionHead() #5 /inc/classes/BxDolRequest.php(57): BxDolRequest::_perform() #6 /inc/classes/BxDolService.php(52): BxDolRequest::processAsService() #7 /inc/classes/BxDolService.php(82): BxDolService::call() #8 /inc/classes/BxDolTemplate.php(3757): BxDolService::callSerialized() #9 /inc/classes/BxDolTemplate.php(1822): BxDolTemplate->processInjection() #10 [internal function]: BxDolTemplate->{closure:BxDolTemplate::parsePageByName():1821}() #11 /inc/classes/BxDolTemplate.php(1821): preg_replace_callback() #12 /inc/classes/BxDolTemplate.php(3817): BxDolTemplate->parsePageByName() #13 /inc/classes/BxDolPage.php(748): BxDolTemplate->getPageCode() #14 /page.php(34): BxDolPage->displayPage() #15 /index.php(35): require_once('/home/kreativm/...') #16 {main} thrown in /modules/msolutions/notify/classes/MsolutionsNotifyTemplate.php on line 16