creating multiple instance with same with single database?

Without knowing more details about the errors and related logs, it isn't easy to diagnose this.

Having worked with WordPress in the past, I expect that the database contains values specific to the WordPress instance that the add-on was installed from, which breaks when trying to reference it from other instances. I imagine not every add-on has this restriction or uses instance-specific values, so mileage may vary for sharing a single DB with multiple WordPress installs.

Thanks friend, while check creating website for multiple instance reduce the site loading, thats why

any other suggestions