Need more detail. Route pair? Could be runway limitations on either end. Is the aircraft you are using a -17R +5.7tn variant? Could you have assigned the route or configuration to a different plane?
Edit: I see the route listed, lemme look.
Hello Zombie - thanks for looking - maybe there's something but I can't figure it out:
Model: 737-200 Adv
Serial No: 24422
Engines: 2x P&W JT8D-17R
Seating: Y:80 C:3 F:0
Nom. Range: 2240
Runway requirement at MTOW: 1680
Lyon Airport (LYS): no issues, its big and I have many other same planes with no issues.
Dakar, Senegal (DKR):
Airport class size: Significant (4)
Longest Runway: 3490 x 45m Ashphalt
Noise regs: all allowed
Allowed aircraft types: all
So what is the quite severe restriction for ?
Nom. Range: 2240nm