You are on ACS and have a transactional event which is linked to Profile schema based on a field, most probably email.
routingFailed means when it tried to connect your event to a template and fetch the personalisation elements something went wrong. In most cases it happens that there is no corresponding profile which the event can link itself to.
Imagin you have defined the event to connect to a profile based on incoming event field cusEmail. The incoming event passes email address firstname.lastname@example.org as the cusEmail value.
When the system tries to fetch the corresponding Profile, it cannot locate one with the same email address.