Hello Aspirant,

It seems that your question is incomplete because it does not includes the name of exam for which you are seeking guidance so it is little bit difficult to guide you accurately. However if the asked message is coming on the exam portal then you have to wait for the admit card to be released and that message is appearing because till now the admit cards are not issued by the exam authorities.

So just wait for it and keep checking the official website regularly for latest updates.

I hope this information  helps you if not then please mention the name of exam.

Good Luck!!