Do you have a "MERGE", "MERGE JOIN" or "UNION" task in the Data Flow? You'll need to combine the derived output of each file into a single set before writing...

Have you tried just removing the database from the AG and next take it out of restoring state by setting it to recovery?

ALTER DATABASE database_name SET HADR OFF

If you right-click on the connection, you can select the "Work Offline" option from the context menu.

You mention there's an app manager involved. Does this manager also manage job in the Windows Scheduler? Are there any errors in the Windows Event logs (system and application) around...

The most common date format in the US is mm/dd/yyyy, whereas in Europe (including the UK) it's more common to have dd/mm/yyyy
So setting the language settings of a login affects the...

Take a look at the free scripts of Kenneth Fisher (https://sqlstudies.com/free-scripts/). He has a script to list all database permissions. You can adjust the script by yourself to...

You can create a specific login for the application to use, preferrably from an Active Directory account. Next create a corresponding database user in each database the application needs access...