HDFC Bank — Credit card declined without any valid reason

Address:

Chennai

I am a HDFC customer for years. I was offered preapproved credit card on my net banking. So I’ve applied for it. I didn’t get any calls or messages from HDFC. But suddenly one day I got a mail saying my application is declined. Now I am not able to apply again. I have my salary account with HDFC and I’ve a very good credit score too. Being a preapproved card, I don’t see any valid reason for the decline. I need proper reason on what went wrong.

Application reference number : 21J[protected]S1