Symptoms
Currently, the New-ExchangeCertificate cmdlet uses the SHA-256 hash algorithm instead of the less secure SHA-1. However, the automatic creation of a default self-signed authentication certificate that occurs during the Setup program calls a different code path than the path that's called by the cmdlet. This causes the program to issue certificates by using the SHA-1 hash algorithm.
Resolution
To fix this issue, install one of the following updates:
Cumulative Update 11 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019
Cumulative Update 22 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016
Important: Our testing indicates that this fix works on only fresh installations. If you apply this fix on an upgraded installation, the program might continue to experience this issue.
References
Learn about the terminology that Microsoft uses to describe software updates.
