migrating subscriptions from ssrs integrated to native mode report server

I am using RS.exe to migrate SSRS reports from integrated sharepoint to pbi report server.  The source reports access sharepoint and use integrated security.  The unnatended execution account is set up on the destination server.  The subscriptions error with -->"The current action cannot be completed. The user data source credentials do not meet the requirements to run this report or shared dataset. Either the user data source credentials are not stored in the report server database, or the user data source is configured not to require credentials but the unattended execution account is not specified."

My Question is,  Is there any pre-work or settings I can use to  copy the subscriptions?   Even if I have to change a config after?   The problem is that when they fail, we have to create them manually ( to/from/params/schedule ..)    So if there was any thing I can do to at least get them to be copied even if they don't work it would save tons of time.

thanks in advance for any advice.

Sean