Starting April 15, 2026, browsers and platforms will distrust DigiCert Global Root CA (G1). Microsoft 365 services use newer certificates, so most users won't be affected. Legacy scenarios may face TLS errors. If issues arise, verify the certificate chain and contact Microsoft Support referencing the April 2026 distrust.
Applies to: Microsoft 365 suite
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).