Terrible relationship with DIL - am I the problem?

My eldest, C (22 years old) started seeing his current partner, A (24 years old) three years ago.

I will be honest, I was, at first, not thrilled with the relationship. First, I was a bit jarred by the age difference. C was born in 2004 whereas A was born in 2001. I worried she might have an upper hand in the relationship, and her experience with life could place him in a subservient role, even though I've raised him to be an independent, assertive young man. Second, I am Korean, and I always imagined my sons - I have two boys, aged 28 and 24 - would end up with Korean women. I would ask him from time to time if he had met any cute Korean girls at university, and every time I would get the same response: "No mom, I have a girlfriend and she is white just like your husband is white." I did not think that was very respectful, but I let it go.

We had a lot of arguments over the years due to some unfortunate statements I made as I suspected the relationship wasn't serious... I may have suggested once or twice that it might be good for him to “keep his options open” since they were still so young. At one point C stopped speaking to me for a bit when I tried to explain that cultural compatibility matters and that Asian women are often better mothers, partners, lovers, etc. In my experience, that is the truth.
To be clear: I apologized if I offended A, as this was not my inten. However, my son and DIL have not been able to let these "rocky beginnings" go, unfortunately.

They eloped in early 2025. It was literally just C, A and their dog. I tried not to take this decision personally. That said, it is hard to come to terms with the fact that my own son did not want me to share this beautiful moment with them... I had to do some reflecting, especially in regards to what kind of mother (and mother-in-law) I had been over the last few years. So I have tried very hard to make things right since she got pregnant. I bought gifts, brought over homemade meals, sent articles about baby care, and apologized, time and again, if I had offended her. I explained myself and even offered some reflections on cultural differences, tips for how to make different worldviews work within a marriage. My husband is white, British born, so I have had plenty of my own experiences. Nothing worked... none of my affection or generosity was returned. It's like talking to a wall. But apparently I am the problem.

A had their son in March. My husband and I were not allowed to be present during the birth or even visit afterward because she "didn't feel right". I understood and respected that at face value, though I heard (from mutual acquaintances) that her parents were there the entire time. I didn't want to assume the worst, but it was more and more difficult not to feel singled out... In the meantime, I tried to be thoughtful, bought lavish gifts for both the new mother and the boy, offered homemade meals. He said they appreciated my effort... but she still "wasn't feeling OK yet", so I was not allowed to see the baby.

I saw my grandson for the first time last week. I felt this had gone on long enough and took initiative, took time off work, and let C know I would be coming by. I don’t think a grandmother should have to beg for permission to meet her grandson. Since this visit, however, C and A have been ignoring my messages and calls, not a clue as to what is going on on their side, as my visit was pleasant and everyone seemed content. A was looking radiant if a bit tired, and the baby was peaceful and calm when I held him.

Have I gone wrong? At this point, I am at a loss. I have reflected, apologized, made efforts, been generous, and shown nothing but love. Meanwhile, A continues to keep me at arm’s length while allowing her own family full access.

How can I get through to A and win her over so that I am allowed to care for my grandson and share special moments with him just like her mother does? Have any of you gone through anything like this?