emails marked not spam still going into spam folder

On the Xfinity web portal.

Thank you for confirming that for me, user_dt0k10! If emails marked as "Not Spam" continue to go into the Spam folder, it may be due to the sender's email provider being flagged as spam by Xfinity's filters. Marking an email as "Not Spam" moves it back to your inbox, but it does not automatically block future emails from that sender. To prevent future emails from going to Spam, consider setting up an email filter to block the sender or domain. This will help ensure that legitimate emails are not misclassified as spam in the future. Please follow this link https://www.xfinity.com/support/articles/spam-filters-and-email-blocking-new-experience for more information on how to set up email filtering and how to block the sender or domain. 

I hope this helps! 

I do not want to block my health care provider, sender or domain.  For many years I have been receiving emails from them with no issue.  Now they go to Spam.  I have not added an email filter to block them.   Per the second response I have added their email to my Address Book.  We'll see.  

@user_dt0k10 Let us know if this fixes your issue.

Having my Health Providers name & email address in our Xfinity Address Book does not stop their emails from going directly into the Spam folder.  How do I correct this issue?