SecureDoc is used to protect laptops so that the disc is encrypted before logging into the operating system. I have Windows 10 on my laptop and normally it's a seamless process to log in where you enter your credentials to SecureDoc on startup and this automatically logs you in to Windows.
However there seems to be an issue when Windows requires a password change and SecureDoc doesn't seem to be able to cope with this so you end up with the situation of needing a different password for SecureDoc to the one used for Windows and need to enter 2 different passwords.
The SecureDoc website is useless for finding information about this and doesn't have any support info - I guess because they expect support to be done by company helpdesks.
The answer seems to be to log in to the SecureDoc control center on your laptop once it has booted into the Operating System. Select the menu option to Communicate with Server and this appears to resync the password between Windows and SecureDoc. I don't know if the same process works for MacOS but it might be worth a try if you find that your password no longer matches SecureDoc.