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Unable to sign in to or sync Samsung Email app

Last updated August 31st, 2023



  • Knox Platform for Enterprise
  • EMMs
  • Samsung Email connected to Microsoft Exchange Server configured for Exchange ActiveSync


After updating the Samsung Email app to version, and your enterprise uses Microsoft Exchange Server and the Exchange ActiveSync protocol, you might encounter an error where you are unable to sign in to or sync your email account.


For Samsung Email or higher, a security patch has been applied to check for a match between the mail server’s fully qualified domain name (FQDN) and the Subject Alternative Name (SAN) in the certificate. Following CWE-297, the mail server’s FQDN should be present in the SAN.

If there is a mismatch between the mail server’s FQDN and SAN, the following email log is generated on the device. In the following example, the example FQDN doesn’t match any of the entries in SAN.

ASHTTPRedirectHandler D executePostWithTimeout(): IOException Hostname not verified:
certificate: xxx/xxx=
subjectAltNames: [,]


There are several methods that your enterprise can employ to resolve this issue:

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