Hi Vignesh, good to hear from you again.
Please ask your question in the Microsoft Credentials forum using link below. There are support moderators over there that will respond to your question in 1 business day and can assist with fixing the issue preventing you from scheduling the exam:
https://trainingsupport.microsoft.com/en-us/newthread?threadtype=Questions&forum=mcp
Please click Accept Answer and upvote if above was helpful.
Thanks.
-TP