Can't make phone calls whilst abroad

[01234]

My phone will not make phones calls whilst in greece. I've tried everything suggested on many forums. It just calls then stops and cancels my signal, any ideas thanks

[Enlli]

Greece has no 3G anymore so unless you have 4G Calling Active then the call has to drop back to 2G, but that's not certain.

Worth checking what happens when you make a call, does the phone go off 4G (LTE)

May be something else but I would start there 

[MI5]

@01234 

Try manually searching for an alternative network, but make sure it's a Greek one