Hi Kartikay,
The problem was that I had a personal free Adobe ID logged in to the Desktop app. I removed that ID, got the original invitation deleted and got another invite which then worked when I signed in with my corporate ID. I have experienced issues using Chrome as my browser though, which may not have helped. Chrome displays blank pages when clicking links from Invitation emails and also from within the desktop app.
I'm on Windows 7 running the most up to date version of Chrome.
Mark