This tutorial describes how to reset the service account password.
Info, Notes and Warnings
Resetting a service account password can cause authentication failures in your fax solution’s environment. This can prevent outbound and inbound faxing altogether.
A service account user and password is typically created alongside the creation of the account itself. These steps can be used to reset the password if the link used to set the password has expired, however, certain accounts do not have the need to use a service account.