A common issue is not having Last Name and Email attributes configured in your SAML Set Up. To diagnose this:
1) Make sure EZRentOut is getting the Last Name and Email for members. The relevant options are available under Settings → Add Ons → SAML
2) Look for typos in SAML Attribute Names added in EZRentOut Settings. For example, if your SAML Attribute for Last Name is last_name, it should be entered as such.
3) In most cases, the parameters/attributes are mapped in your preferred identity provider configuration settings, otherwise your service provide will ask you to map them.