Hello Harry Potter,
Thanks for reaching out. Graph API v1.0 auditLogs/signIns endpoint only returns interactive login. Per article https://learn.microsoft.com/en-us/graph/api/signin-list?view=graph-rest-1.0&tabs=http
"Retrieve the Azure AD user sign-ins for your tenant. Sign-ins that are interactive in nature (where a username/password is passed as part of auth token) and successful federated sign-ins are currently included in the sign-in logs."
However the beta version of the auditLogs/signIns endpoint does return non-interactive logins as well. Please refer to article https://learn.microsoft.com/en-us/graph/api/signin-list?view=graph-rest-beta&tabs=http for more information and examples to retrieve non-interactive sign-ins. Note that APIs under the /beta version in Microsoft Graph are subject to change. Use of these APIs in production applications is not supported.
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Thanks.