For G Suite.
For Office 365.
How can I control access to HENNGE Email Archive Admin Console?
You can restrict users from accessing the Admin Console based on source IP addresses.
[How to Set Up]
1. Login to Email Archive Admin Console with administrator privilege.
2. Go to [Console] > [Console Settings] on the left side menu.
3. Click on [Edit] in the [Allowed Access] section. The [Change Access Control] popup will be displayed.
4. If [Allowed All Access] is selected, change it to [Select Allowed Access].
5. Specify the IP addresses or Network in CIDR format(e.g. 192.168.0.0/24) that you want to allow to the [Allowed Access] box.
*Multiple addresses can be specified with line breaks.
6. Click on the [Save] button and the changes will be saved.
Please be careful about the IP addresses you set. If the wrong IP addresses are set, you may not be able to login to the Admin Console once you logout.
You can also hide the admin menu per user.
Reference:How can I set access rights for users to access HENNGE Email Archive Admin Console?