Hi frenklee,
Thank you for giving us the chance to assist you with your Apple Watch. You can count on us to do our best to assist you or get you pointed in the right direction.
We understand that you are experiencing issues getting a reading on the Blood Oxygen app.
We’d like to gather additional details that may help us be in a better position to assist you.
Would you please tell us which watchOS version you are using?
Are you experiencing any issues with other features of your Apple Watch?
Are you receiving any error messages when using the Blood Oxygen app?
Also, the article below may help.
How to use the Blood Oxygen app on Apple Watch Series 6
Please keep us posted.
Take care!