New Edge Subscription fails withh error dubplicate certificate

we have a one third-party certificate , in our old 2016 environment we use the same certificate on edges and mailbox servers without any issues so why will it not work on new exchange 2019 environment ?

Microsoft officials did not elaborate on why the same certificate cannot be used, but they just emphasized this point. The certificate on Edge must be issued from the same CA and have the same subject name as the cert on the mailbox server, but they must be different certificates.

See: https://video2.skills-academy.com/en-us/exchange/certificate-requirements

"Each Edge transport server must use a certificate that shares the same issuing CA and the same subject for hybrid secure mail to function correctly."

And this article:https://www.informaticar.net/how-to-install-and-configure-edge-transport-on-microsoft-exchange-2019/

It also points out that "You should not use same certificate for both edge and mailbox server because you will get error like this.

If you use wildcard cert on the mailbox role (this is only example), you should create new certificate request and get for example edge.yourdomain.com or smtp.yourdomain.com certificate for the edge role (doesn’t have to be wildcard certificate and name is also provisory).

This also means that you will have to recreate edge subscription after you get new certificate."

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