Sending S/MIME encrypted messages with Outlook for iOS is not possible: "There's a problem with one of your S/MIME encryption certificates."

Assume the following scenario:

There's a problem with one of your S/MIME encryption certificates. Contact your IT help desk for more info.
There is a problem with one of your S/MIME encryption certificates. Contact your IT help desk for more information.

Do you know TameMyCerts? TameMyCerts is an add-on for the Microsoft certification authority (Active Directory Certificate Services). It extends the function of the certification authority and enables the Application of regulationsto realize the secure automation of certificate issuance. TameMyCerts is unique in the Microsoft ecosystem and is available under a free license. It can downloaded via GitHub and can be used free of charge.

Possible causes

If Exchange Online fails to locate a trusted root certificate or fails to contact the certificate revocation list for the certificate authority, that certificate is considered invalid and is not trusted.

S/MIME for Outlook for iOS and Android in Exchange Online

Related links:

External sources

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