It's the radar map blocker - usually a sign that something in the campaign script isn't working properly.
Background: this blocker is enabled by default and therefore every campaign script needs to have an entry that disables it - it's a simple line like this:
restrict_strat_radar false
Check if that entry exists in the script - if it does then something is wrong with the script and you need to check the log. Else use Squid's campaign script checker.