Verify Microsoft Purview Message Encryption configuration in Exchange Online PowerShell You can verify that your Microsoft 365 tenant is properly configured to use Microsoft Purview Message Encryption in Exchange Online PowerShell.
1. Using a work or school account that has sufficient permissions in your organization, such as Compliance Administrator, start a Windows PowerShell session and connect to Exchange Online.
For instructions, see Connect to Exchange Online PowerShell.
2. Run the Get-IRMConfiguration cmdlet.
You should see a value of $True for the AzureRMSLicensingEnabled parameter, which indicates that Microsoft Purview Message Encryption is configured in your tenant. If it is not, use Set- IRMConfiguration to set the value of AzureRMSLicensingEnabled to $True to enable Microsoft Purview Message Encryption.
Reference:
https://docs.microsoft.com/en-us/microsoft-365/compliance/set-up-new-message-encryption-capabilities