Here my AP certificate with the expire date of 14.June 2018
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If I check the MIB apCertificateExpiry=1.3.6.1.4.1.4329.15.3.5.2.2.1.13 the output value is 176 days but June 14 is in 142days so that is a 32day difference.
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NTP on the controller is correct.
Any ideas why the value is wrong.
-Ron