Why am I getting the Invalid boards Warning?
About the Unsupported boards Warning Dialog
This dialog appears in several specific cases to inform the user that certain boards cannot be added to the Routemap board.

Below are the common scenarios in which you might encounter this dialog.
1. Kanban Projects or Kanban Boards
If you create a Routemap board using a Kanban project or Kanban board, the dialog will appear to inform you that these board types are currently not supported in Routemap.
2. Board Location Conflicts
When a board’s main location is tied to a project that is not included in the Routemap board, the dialog will appear.
Example:
Board X is created from both Project A and Project B.
However, its main location is set to Project A.
If a user creates a Routemap board based on Project B, Board X cannot be added to it because its main location does not match the selected project.
3. Board Location Outside of Selected Projects
The dialog will also appear if the board's location is not associated with any of the projects included in the Routemap board, such as:
The board is located under a user profile instead of a project.
The board has no defined location.