Activate Spam Folder in iOS Mail App for Yahoo E-mail AccounT??

Recent changes in the Yahoo email system seem to have hidden the way to activate the Spam folder. When one enters a Yahoo account to the iPhone in iOS 12.x it automatically connects to the IMAP server (as oppose to the POP/SMTP servers. All the folders from the desktop Yahoo Mail website appear, however, the Spam folder is grayed out and cannot be accessed. 

How does one activate the Yahoo email Spam folder in  iOS Mail app so it can be accessed and syncs with the desktop Spam folder addresses?