This issue might occur when you have O365/AAD enabled on the server. The product team is investigating it, in the mean time, the following workaround might help mitigate this issue:
1. On the server, go to folder %programfiles%\Windows Server\Bin\FeatureDefinitions\Microsoft PwdSync\
2. Make a copy of file Definition.xml for backup
3. Edit the original Definition.xml (if you don’t have permission, copy the file out, edit it and put it back in the folder):
Comment out the following two sections:
<HealthDefinition Name=”PasswordSyncOtherFailure” …
4. Restart WseEmailSvc windows service.
Please let me know whether it helps nor not.