Microsoft Dynamics Marketing administrative users will receive a "Your Azure authentication certificate is about to expire. Click here to renew it." alert within the application following the Microsoft Dynamics Marketing version 17.1 upgrade. This alert will only appear if the Microsoft Dynamics Marketing/Microsoft Dynamics CRM connector has been previously configured.
To ensure that the Microsoft Dynamics Marketing/Microsoft Dynamics CRM connector continues to function after the previous certificate expires, please perform the steps listed in the following KB article: http://support.microsoft.com/kb/3036060?wa=wsignin1.0