Grandparents and grandchildren have a special connection and this is a great reality. Grandparents who live far from a grandchild are especially prone to causing strange anxiety in young children. Being a grandparent and being at a distance can have a negative emotional impact on children and this causes some rejection ... For this reason it is necessary that even if you are in the distance you continue to be a good grandfather to your grandchildren.
One idea is to use the Skype program or Fcabeook's FaceTime so that the grandchildren get used to their faces and their voices. You can make video calls to make them as interactive as possible and thus be able to work on a good emotional bond with the grandchildren. By doing this, children will not feel as much rejection when they see grandparents in person again.
Playing games or singing songs is one way to get a young child interested in video calling with grandparents. Still, there is no guarantee that you won't provoke (temporary) tears of rejection when you show up in person. Some babies and toddlers are confused when someone they meet via video chat shows up in real life. For all these long-distance dilemmas, frequent visits or extended visits will help you more than anything else.
It is also possible that the baby or young child has a strong temperament and that when they see their grandparents after a while they may feel some anxiety. This does not mean that children will always be afraid or anxious when seeing their grandparents, but if the grandparents become involved in their life little by little the little one may feel more secure and able to control anxiety.
The important thing is to work every day so that your grandchildren can have a bond with you, even if you are far away.