You have created a new Quarantine Administrator, but the account is unable to view or release Quarantine messages.
Email Security.cloud
The Administrator's account was either created under user quarantine Custom settings while the domain is on Global settings or Vise versa.
The Administrator managing accounts must carefully check if the newly created account was applied to Custom settings while the domain is on Global settings or Vise versa.
Below is an example of the Apply to Global Settings :
If a domain is using Custom Settings :