Error 404 xml ssodata

[Mike31]

Hi,

I have an error in web browser console when I launch auth0 login page (auth0.js v9) :
Erreur d’analyse XML : aucun élément trouvé
Emplacement : https://.eu.auth0.com/user/ssodata
Numéro de ligne 1, Colonne 1

In network part, I have an 404 error on ssodata because the response is empty.
It’s not blocking but I don’t know why I have this error and which tenant parameters could be fix this error.
I specify I do not use Auth0 sso fonctionality.

Thank you

[nicolas_sabena]

Hi @Mike31.

TL;DR: the 404 from /user/ssodata is no cause for concern. Read below for more details.

When a user already has a session in Auth0 and an application requests a new token, Auth0’s Lock used to present a “Last time you logged in as john.doe@acme.com” button in the hosted login page that would let you reuse the existing session easily (no need to enter credentials again).

New tenants (or existing tenants that turn on “Enable Seamless SSO” in the tenant advanced options) behave differently: if the user already has a session in place then the login step is skipped completely so that the hosted login page is not even displayed (although the user might see other prompts such as MFA or consent).

When this “Seamless SSO” functionality is enabled (which, again, is the default and only behavior available on new tenants) the /user/ssodata returns 404, because its functionality is not really needed anymore.

Lock still tries to call /user/ssodata anyway (because Lock, running in the browser, is unaware of the tenant configuration), but when getting a 404 response it simply assumes that there’s no session in place (which is the right assumption to make, because if there was a valid session then the login page would not have been loaded).