If your Litchi altitude is set higher than the maximum in DJI Go, you'll get that message. For instance, if your max altitude setting in DJI Go is 300 ft and you set Litchi to go to 350 ft, you'll get that message until you change the setting in DJI Go.
If you haven't logged into DJI Go and have the latest version, it'll limit your altitude and that will probably carry over into Litchi. I'm guessing on that because I haven't updated DJI Go in a while so I haven't had to sign in.
I usually keep my max alt in DJI Go set to 400 ft but tried to load a Litchi mission and got the same message. It was because one of my waypoints was set to 430 ft (to maintain 400 ft AGL over a small hill). I opened DJI Go, changed my max altitude to 450 ft and the Litchi mission loaded and ran fine.