insert with autoincrement fails

I cant get a table insert to work via the an elementary form that is not a tabulation. The table has an auto-incrementing field defined as integer. I have not been able to define this field formally as a Primary Key, which bothers me slightly. The form fails when I omit the auto-incrementing field, which should work according to me, and when I include it which is not a surprise.

Do all inserts have to be done via the tabulation? Or is there a PK feature somewhere that will fix this?

Hello,

You have not included some basic information - OS, specific LO version, database being used.

When creating a table using Create Table in Design View... and you set a field to auto increment, it automatically is set as the primary key. How was the table created?