Using line on multiple IP

Just wondering if you experts can assist me, I brought a new skybox f3s for my brother as a present, it came without a gift.

So as recommended I purchased a line for the box, all set up and working at my house.

I gave it to my brother to use and it worked for a day and then he noticed it said no signal on the sky channels.

Is this caused by the box moving house, thus it has detected a new IP, so has stopped the line, as I have read that the line can only be used on one IP.

Is this the problem?