Outlook deeplink for email compose replaces spaces with ++ when user not logged in

[sowmyav]

Hi,

I am using the Outlook 365 deeplink URL to open a new email in compose window from my web application.

This is the deeplink URL I use: 

https://outlook.office.com/mail/deeplink/compose?&subject=.....

I use window.open() to open the above URL. If I am not logged into outlook and I invoke the above URL from my application, I get the outlook 365 authentication redirection and once I successfully login, I see the outlook compose window with my contents (subject, body). But the issue is that all the spaces are converted into + signs. I dont see this issue if I am already logged into outlook 365 before invoking the deeplink URL. Could you pls let me know how to fix this issue?

thanks

Sowmya