Thanks folks for your help. This is a great forum. I am learning a lot.
I have my application working again. I came across an article on steps to take before upsizing an Access database.
Step 1 is to remove any random autonumber field. I had not done that, and even when I changed the field properties in SQLServer it would not work. So I went back to Access and changed the primary key to an int. After upsizing, I made the primary key an Identity.