Issue Windows changing smartermail DNS

[TheHostingHeroes]

When Plesk updates we have found that it is making changes to smartermail DNS

for example in protocol settings in smartermail we use google dns 8.8.8.8 / 8.8.4.4

plesk is changing it to IPv6 DNS and we don't support IPv6 so all emails then fail for our customers as smartermail cant resolve the IPv6 DNS servers.

 

[PavelV]

During reconfiguration of SmarterMail Plesk reads DNS settings from system (DNS servers settings from Network adapter).
If there are IPv6 addresses specified and if you are using SmarterMail 11 or higher, then Plesk will set all IP addresses including IPv6 to the SmarterMail.
Currently this behavior is by design.

As I understand, you have configured SmarterMail to use its own DNS settings. So DNS settings on network interface and in SmarterMail are different.
Is it possible for you to update DNS settings in system as well?