Please take the backup of your current original single.php file from your theme.
After that you should add that single.php file (form your old backup) to your current theme and check if you able to see the frontend single page working as expected.
When I checked I see the following fatal error:
Fatal error: Uncaught Error: Call to undefined function cjpaco_package_content() in /home2/willicf7/public_html/wp-content/themes/accelerate/single.php:19 Stack trace: #0 /home2/willicf7/public_html/wp-includes/template-loader.php(106): include() #1 /home2/willicf7/public_html/wp-blog-header.php(19): require_once('/home2/willicf7...') #2 /home2/willicf7/public_html/index.php(238): require('/home2/willicf7...') #3 {main} thrown in /home2/willicf7/public_html/wp-content/themes/accelerate/single.php on line 19
There must be function cjpaco_package_content() available either with your old theme's functions.php file or somewhere else I do not know as I do not know the site history.
Can you please share your old theme files zip backup with me? You should upload it on any file sharing service and share the link to download the zip.
Ok - I find a way to download your backup theme from FTP but there are many issues and we are not allowed to debug themes.
The only thing I would say is, rather dependent on your single.php file, I suggest you should create content template for your single post for your post type from Toolset => Content Templates and where you need help you can raise a ticket here.