Accessing Mimecast Portal
Access portal at this address:
https://login.mimecast.com/m/portal/login/#/login
You will be asked to enter your email address
Once you have entered your email, click next
You will be taken to the Microsoft Single Sign-On (SSO) screen
Complete your microsoft login
You will now be able to access your Mimecast portal, which gives you access to your email as well as the possibility of releasing emails that are on hold: