Sometimes you can see notifications in Magneto 2 panel that are displayed over and over again. This is Magento 2 admin notifications.

Magento 2 Admin Notification

To stop showing these messages you need to mark them as read. 

For this please navigate to Noficiations Manage page. Click on the bell icon in the top right corner in the admin panel and then press the "See All (X  unread)" link.

Magento 2 Admin Notification Popup

Select the messages you want and mark them as read.

Mark Magento 2 Notification as Read

Tha's all.