Entity does not execute command

I am making a minecraft mod with different planets and cargo rockets. Those cargo rockets can be placed and "tamed" and then they should fly to a port-block. My problem is that i use commands to teleport the rocket (because i think it is a simple way, maybe there are other ways to do it idk) but the rocket just falls down to where it was placed. 
 

I added a "Send to chat"-Element to see if the command is wrong but if i use the command manually it works. So does anyone know where the mistake is? Or does it even work?

The variables are also correct. There is one variable for the dimension (planet) and one with coordinates (it is called port_1 in the image).