Hi ken,
Thank you for using Samsung Home Appliances for your home. We are here to help with your Samsung range especially with the door.
After performing a self-cleaning cycle, the oven door will stay locked until the oven temperature drops below 400°F.
I have shared a Samsung link below that will guide you through some steps to help open the door.
The oven door is locked:
https://www.samsung.com/us/support/troubleshooting/TSG01001957/
Should you need more assistance, please feel free to get back to us via the following options:
1. Facebook Messenger: http://m.me/samsungsupport
2. Twitter: https://twitter.com/messages/compose?recipient_id=18768513
3. Samsung Community: https://us.community.samsung.com/t5/Samsung-Community/ct-p/us
When you message us, provide us with this reference number 1145046222, it will help our team pull up your information.
Leo