@David-TP dear David, thank you for your answer. Unfortunately apn is not the issue: I need to stick to the same network operator as the signal form the others is better therefore when the signal of my operator disappears the router will connect to the wrong one and never come back to the correct one. This setting is "manual" on many phone settings instead of automatic. It seems an update was release for more recent versions of the router but not for this one 2.0

  @David-TP yes, that's what I was talking about :) I cannot say since which version the setting was available or made available via update. Quite a basic one, though. Probably the product was meant to use sim card as a fallout solution only and not really to generate a network based solely on 4G connection. thanks again Ivan