Error : “Master password sanity check failed – invalid master password provided” is due to the fact that your master has expired or invalid.
Please refer to the 8-2-SP2_Administering_Integration_Server.pdf guide, under “Determining Whether You Can Restore the Passwords”. I have copied some information for you below (you may have to refer the guide for more information)
You can restore passwords if either of the following is true:
a) Your master password and outbound passwords are stored in files and you have recent backups of both and the passman.cnf file.
b) The Integration Server is configured to prompt for the master password, you have a recent backup of the outbound password file and the passman.cnf file, and you know the master password for that backup.
Try this and this should resolve the issue if not uninstall the software (following my procedure) and install it freshly.