If the feature is OOTB and not customized, then I recommend to create INC ticket to get the clarification from SME (if it’s intended by design or defect).
Hello @prasada4
first of all welcome to the community. Thank you for taking time to share your experience. this is how we learn 
so i see that you are already viewing content on the pop up window. i have feeling that you are prevented to open the pop-up from the pop-up window.
remember in the real situation this email will be landing in the email of the recipient and will not be presented as popup.
can you see the URL for that link? can you copy and try to open the same on another browser tab?
Also what browser are you using ?
Hi @Amey_Thombre Many Thanks for your reply and made me the confidence on this . I have received the email to my outlook and able to open the email with content . I was assume it should work with in application . As per explanation understand with in application is not real time scenario .
Hi @RameshSangili Many Thanks your support .
