Second cousin but how?
Got a second cousin match (212cM) with a guy who is early 30s, I am mid 50s. It's my dad's side of family and he's adopted so I'm sort of fumbling blindfold through these matches. He is also estimated as 2C (207cM) to another match (same age as me, 303cM) and to me, so I'd assume we all have shared great grandparents? Except...I've done a private tree for him which I'm pretty sure is right, and I can't link his grandparents to 'my' family at all. They lived in rural Ireland in the early-mid 20th century and his people were 80 miles away in Dublin. One of his grandmothers is hard to trace pre marriage so she may be the link.
He may be 2C1R given his age and the lowish cM, which would make his parent my 2C. Still no clearer about how we are related. Realistically, am I looking for illegitimacy or adoption? He doesn't use Ancestry much and hasn't replied to my message
(which was v neutral and vague). Is there any way of viewing an Irish marriage certificate from the 1950s which might throw some light on the grandmother?