Write Conflict, Linked Table to Access 2016

I have SQL Server Express and have linked a table to MS Access. I get a write conflict error, stating that the record has been changed by another user, but I am the only user.

I can edit the data using SSMS, but if I open the table in Access, I cannot. I did have a date/time field constraint, but removed the field and the problem persists.

Advice? Thank you.

Do you have a primary key defined on the table?

Yes, primary key is set.
Just got this figured out, I think. I have two bit type fields and only one had a default value set. I ran an update query for both fields, since those values don't matter much at this point, only after I go live does it matter.
Then, I added the timestamp field back in and so far it seems to work.