Can't save draft post

I have a WordPress site moved to Azure web site + Azure SQL using database abstraction plugin

After that migration I’m not able to create new posts. When I click Save Draft it redirects me to the Posts page and my post isn’t saved.

My network capture is in this order:

wp-admin/post-new.php -> 302 Moved Temporarily (post_ID = 0)

        wp-admin/admin-ajax.php -> 200 OK

        wp-admin/post-new.php?message1 -> 302 Moved Temporarily

        wp-admin/edit.php -> 200 OK

But I’m able to create new post from Quick Draft with this network traffic:
This happening regardless of the WordPress version.

The SQL table definition seems Ok, being IDENTITY property the same as auto_increment in MySQL.

CREATE TABLE [dbo].[wp_posts](
[ID] [bigint] IDENTITY(1,1) NOT NULL,
[post_author] [bigint] NOT NULL,
[post_date] [datetime] NOT NULL,
…)

I have disabled all plugins with no effect and I’ve deleted and copied again all files with no effect either.