Are you sure you don't have a typo in your username/password combo in either icamsource or the iCam app on your phone? Try retyping them in both places.
If that doesn't work, have you tried checking the "Auto config router" box in icamsource and ensuring that uPNP is enabled in your router? In my experience, this is usually only needed if you have more than one camera connected to icamsource.
If neither of the above works, you might have to set up manual port forwarding...which is a bit of a pain, but is rock solid once you get it set up.
