Why am I unable to sign in after changing active directory username?

Please enter ?debug=1 appending the remote login URL and verify if the email attribute is passed successfully through which authentication for Simple SSO takes place.

If you are using SAML based SSO, then verify if the user profile has access to the SAML app and try adding the user manually into Freshservice and then they should be able to log in.

Please write to it.helpdesk.abcinc@gmail.com m if you need further assistance.