Forum Discussion
Neymar
Feb 12, 2026Copper Contributor
Exchange 2019 Certificate Error
Hello guys, I plan to migrate my users on Exchange 2019, currently, i have 2 Exchange 2013 servers. As soon as i installed the exchange Server 2019, I changed all the virtual directories and i also ...
AnnTaeYoun
Feb 12, 2026MVP
Hello! Neymar
The certificate name mismatch occurs because the newly added Exchange Server 2019 is being accessed directly by users' Outlook clients.
To resolve this issue, block inbound TCP port 443 traffic from client networks to the Exchange Server 2019 IP address at the firewall level.
This will prevent direct client connections to the backend server and ensure that Outlook connects only through the designated load balancer or Client Access endpoint.
Neymar
Feb 13, 2026Copper Contributor
Hello AnnTaeYoun
Thanks for your answer, but even by doing this, the pop up that says that the certificate is not correct still appears.