@Krishna
It must be hard to have your daughter not speaking with you. But be comforted that it is more a reflection of how much she is struggling at the moment, not of the relationship between you.
I have find it difficult to speak with my mother about mental health issues. When I was in a mental health unit I also refused to let her visit, or find out anything about how I was. The psychiatrist still talked with her, but couldn't tell her anything about me or my health. The psychiatrist would tell me what my mum had said and encouraged me to accept her support, insisting that I was discharged into her care.
Being in a psychiatric unit, on top of my very fragile mental health - there were lots of things I just couldn't cope with. Talking with my mum was one of those things. I was ashamed of being in there, and of the negative judgements made by the nurses. I didn't want my mum to see me in there or be told the things they were making up about me.
Even when I have been out of hospital, I often avoid talking with my mum. I don't answer her phonecalls if I don't feel up to being cheery and pretending everything is ok. When I do talk with her I avoid many topics that make me uncomfortable including about my mental health. Often all I would talk about was my dog. She kept trying and I knew she would help me if I needed her too. I found it easier to discuss my mental health struggles with professionals and a few close friends. Until recently when my friends and professionals at the hospital majorly let me down & I needed my mum's help. I still couldn't talk with her directly & asked others to contact her on my behalf. It has been very difficult for me to open up to her after such a long time, but I had to.
So just let your daughter know that you are there for her, if and when she is ready for your help. Perhaps offer support or communication in other less challenging ways - send her a card with a few words of support, a photo, a small gift to support a hobby. In a fragile state, even the smallest thing can trigger a memory of something unhappy, or even something that was previously a happy memory, but now seems lost. If possible keep things in the now, without worry of the future or memories of the past. Don't put too much pressure on her to respond. I know I felt guilty that I was not able to talk with my mum, or not able to be honest with her about my mental health, but I was overwhelmed and just not able to do it at the time.
Also important that you look after your own mental health and seek support to help you get through this challenging time.
Best wishes.