Hi Srinivas,
Do you have at least one of the prerequisite certifications (Azure Developer AZ-204 or Azure Administrator AZ-104)? At least one of these is required in addition to passing AZ-400 in order to earn the certification.
Please ask your question in the Microsoft Certification forum using link below. There are support moderators over there that will respond to your question in 1 business day and can assist with getting your certificate to show up:
https://trainingsupport.microsoft.com/en-us/newthread?threadtype=Questions&forum=mcp
Please click Accept Answer if above was helpful.
Thanks.
-TP