Thank you for contacting us. I'm not sure what's happening here, but if you are signing in to the same account on your MacBook that you are signed in to on your other devices, you shouldn't have any problems. I'm going to have you check the username in mSecure's Account Settings on each of your devices.
For the mobile app (iOS):
For the Windows app:
Which email address do you see next to the Username field in each of your mSecure apps?
I have been trying to sign in for the first time on my MacBook and its giving me "Invalid username/password". I have my iPhone, iPad and Windows working fine and properly, just cannot figure out why I cannot get mSecure on my MacBook.