Microsoft regularly updates the certificates in Microsoft 365 (formerly Office 365) in order to always provide a highly available and secure environment.
From 23 January 2021, a certificate change will now be made every six weeks on the Microsoft Federation Gateway. This can lead to problems with Exchange hybrid installations that use this gateway. These are installations where you connect your local Exchange Server with the Exchange Server from Microsoft 365 (Exchange Online). They are usually carried out when one synchronises a local Active Directory with the Azure Active Directory of Microsoft 365 and wants to use Exchange Online. The certificate update must be made known to the local Exchange Server manually. This process can be automated via a script.
We recommend that you make the settings promptly to avoid problems in your installations. Microsoft provides further information here.
If you have any questions about the facility, we will be happy to advise and support you. We look forward to hearing from you.
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