Supply ships cannot move

[mtodd]

Playing as the Japanese, I cannot move some supply ships to other regions. Even to an adjacent region.

I can see no reason for this.

Any help appreciated.

[JanSorensen]

If you already have supply ON the ship it cannot move (except in rare cases you never should leave supply on the ships anyway).
The same applies if you move any cargo (supply or units) using the transport - then it cannot move that turn.
If you are playing with advanced supply and area supply then I suggest turning the latter off as that makes it harder to control when supplies are moved across ships.

[mtodd]

Thanks