Cirrus employs a security certificate, commonly referred to as an SSL certificate, to encrypt data transmitted between your M365 environment and the Cirrus application. To maintain the continuous and secure encryption of your data during the transmission between your M365 environment and Cirrus, you may be required to re-authenticate your connection, similar to the initial setup process. In the event that your SSL Certificate has expired, it can result in backup jobs encountering failures, accompanied by an error message:

If your SSL Certificate has expired then your backup jobs will start failing with the error message:


AADSTS700027: Client assertion contains an invalid signature. [Reason - The key used is expired., Thumbprint of key used by client: 'ID', ... ]

We offer functionality that allows you to either use your own security certificate or have us generate one for you automatically.

To have Cirrus generate a new SSL Certificate, please follow the steps below:

1) Log in to Cirrus with an Admin Account.

2) Click the Settings tab in the bottom left of the window.

3) Click System.

4) Click the blue Generate a new certificate button.

5) Copy the code that Cirrus provides on the next screen.

6) Open then paste the code and follow the steps given.

7) Once the Microsoft steps have been followed, click Generate in Cirrus.

Help & Support

If you require assistance, you can access online help at