Android and data roaming

[theleg]

ok, have a three sim in a samsung galaxy J7. Sim works for regular calls in the UK and data works.

Need to take it to europe so tried to enable data roaming but the option is greyed out. No way to switch it on.

Any clues why it would be greyed out? What am i missing?

 

[Orcvader]

Is it an unlocked EU J7? Searching around it seems to crop up with Romaing Guard but that seems to be a Sprint thing.