Nested sub form MS-Access on tabbed form using SQL SERVER Express

I have migrated an access mdb to SQL Server Express to improve performance and access for external users via vpn. The issue I have remaining is a nested sub form on a tabbed form that uses record selector and navigation bar. Previously before the migration the nested sub form would allow changes to the edited record via dynaset recordset also a new record could be created on the sub form after selection of options in 3 combo boxes were completed. After creating a unique index on SQL side I am able to make changes to exisitng records but I am unable to create any new records through the navigation bar by clicking on the arrow/asterick as usual. This option is now grayed out. Any thoughts, ideas or suggestions. I have already figured out that I could separate the form and create a whole new form by itself and it works fine. I'm trying to avoid this. If I have to write navigation code I'm not beyond that but would need to know where to get snippets of code to get started.

Thanks,
~Annette Curtis
Sr. Information Analyst

So if you just open the subform by itself can you add a record? Have you tried replacing the subform with the new form that works? I've seen that happen before that a particular form gets corrupted but a copy of the form works fine.

I have seen issues with SQL if tables have the same field name and you do a join, addditional records are disallowed.

I ended up creating it as a new tab on its own now I have no issues with SQL.