Hello @Richard Huang
Thank you for reaching out. SCIM quarantine can happen due to multiple reason. However as per the error message you typed "you appear to have entered invalid credentials, administrative account." It seems an incorrect value was used to establish connection between Azure AD and Apple School Manager.
I would suggest you to please follow the following documentation Configure Apple School Manager for automatic user provisioning and complete the step 5 appropriately. The credentials used to configure automatic user provisioning would be SCIM 2.0 base URL and Access Token value which are available on Apple School Manager Admin page.
Other Quarantine scenarios for Azure AD SCIM are discussed in following article: Application provisioning in quarantine status.
I hope this answer helps to resolve your issue.
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