Nerdio Admin Portal (NAP) communicates with Office 365 using a @tenant.onmicrosoft.com account. When provisioning a new Office 365 tenant NAP sets the admin account's password to never expire. If the password expires the NAP integration will break.
NAP allows you to use your own Office 365 tenant. If you do bring your own Office 365 tenant, then make sure to set "Password never expires" to ON in Office 365. Visit the Admin Panel in Office 365, look for the Settings menu and then navigate to the Security option.