Hi PatDesro, please try the below steps and get back to us with the results.
Setting up a Dynamic Lock Screen.
1. Head into your Settings > Lock Screen
2. Select Wallpaper services
3.Tap on the Dynamic Lock screen
4.Select the Dynamic Lock screen Settings
5.Tap on the Select category
Ensure you have enabled Auto-update, if this setting is enabled the wallpaper in your current rotation will be updated automatically from time to time.
6.Tap on the preferred theme to download
7. Select Download. Ensure you are connected to a strong internet connection.
8. Once installed you will be able to view your Dynamic lock screen
Using your Gallery
Head into your Settings > Wallpaper
Choose up to 15 photos or videos to add to your wallpaper then select Done.
Select Set on the Lock screen.