Unable to find a solution that satisfies your constraints. 

This could be because:

• You have a constraint of "Min Players Per Decade", but this requires more players than available roster spots.  Try reducing "Min Players Per Decade" or increasing "Max Players Per Position" constraints.

• You have selected a team that was not active in the decade(s) that you've selected.  Try increasing the "Min Decade" or relaxing the "Team" constraints.