EDIT 2/4/2026: We’ve been notified that some email providers may distrust the DigiCert G1 root on April 15, which could result in broad ecosystem‑wide email impact. To ensure Exchange Online can rota...
Updated Feb 04, 2026
Version 3.0
Blog Post
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Trust DigiCert Global Root G2 Certificate Authority to Avoid Exchange Online Email Disruption
Can we get a list of name spaces that apps would use to send to Exchange Online like smtp.office365.com?
Arindam_Thokder
Microsoft
MicrosoftNot sure if I understand the question. You mean servers behind smtp.office365.com? No, those could change anytime.