RE . . you asked for the results of this command - below.
It shows the an expired certificate and the new certificate both assigned for client services.
is that the problem ?
When I ran the command to enable and assign the new certificate, it asked if it should overwrite the existing certificate . . I said Y
I didn't remove the expired certificate manually because i didn't want to break the services.
RE . . I restarted the server to see if the status of the new certificate would change, before I submitted this question.
[PS] C:\Windows\system32>Get-ExchangeCertificate | FL
Creating a new session for implicit remoting of "Get-ExchangeCertificate" command...
AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule, System.Security.AccessControl.CryptoKeyAccessRule}
CertificateDomains : { REDACTED
HasPrivateKey : True
IsSelfSigned : False
Issuer : C=US, S=mn, XXXXXXXXXXXXXXXX
NotAfter : 5/1/2022 11:51:46 AM
NotBefore : 5/1/2021 11:31:46 AM
PublicKeySize : 2048
RootCAType : Unknown
SerialNumber : 43771D1FAD78D3A749FEAF8C32AF99CF
Services : None
Status : PendingRequest
Subject : C=US, XXXXXXXXXXXXXXXXXXXXXXX
Thumbprint : 23EE9686373E31E6364872C3A371F0B2F945FCBA
AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule}
CertificateDomains : {owa.contoso.com, www.owa.contoso.com}
HasPrivateKey : True
IsSelfSigned : False
Issuer : CN=XXX
NotAfter : 5/1/2022 6:59:59 PM
NotBefore : 4/30/2021 7:00:00 PM
PublicKeySize : 2048
RootCAType : ThirdParty
SerialNumber : 00BED1EA8B7153E827C2A00A4B4C5C5A1E
Services : IMAP, POP, IIS, SMTP
Status : Valid
Subject : CN=owa.contoso.com
Thumbprint : 5B319E743D3D4C6BFBC22D41CBF02F3B8192254F
AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule}
CertificateDomains : {owa.contoso.com, www.owa.contoso.com}
HasPrivateKey : True
IsSelfSigned : False
Issuer : CN=XXX
NotAfter : 4/29/2021 6:59:59 PM
NotBefore : 4/21/2020 7:00:00 PM
PublicKeySize : 2048
RootCAType : ThirdParty
SerialNumber : 3D14FBF4D3E899E1CE571572DEA54946
Services : IMAP, POP, SMTP
Status : DateInvalid
Subject : CN=owa.contoso.com
Thumbprint : 0B7A2F0232FA0F315FF6C4F7D62018C25AEBFF33
AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule}
CertificateDomains : {ex2016, ex2016.mail.dmz}
HasPrivateKey : True
IsSelfSigned : True
Issuer : CN=ex2016
NotAfter : 5/5/2023 5:25:15 AM
NotBefore : 5/5/2018 5:25:15 AM
PublicKeySize : 2048
RootCAType : None
SerialNumber : 1B26109BE2FC909C4E8B79CF615400CC
Services : SMTP
Status : Valid
Subject : CN=ex2016
Thumbprint : D6B99B18963707B482C654A8791B358FC70F76AA
AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule}
CertificateDomains : {}
HasPrivateKey : True
IsSelfSigned : True
Issuer : CN=Microsoft Exchange Server Auth Certificate
NotAfter : 4/8/2023 1:02:26 PM
NotBefore : 5/4/2018 1:02:26 PM
PublicKeySize : 2048
RootCAType : None
SerialNumber : 6AEFCC8017ECAD9A43874F83D9C23982
Services : SMTP
Status : Valid
Subject : CN=Microsoft Exchange Server Auth Certificate
Thumbprint : 42E32369DA3D146E4E0C666653F98F47606C296C
AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule}
CertificateDomains : {ex2016, ex2016.mail.dmz}
HasPrivateKey : True
IsSelfSigned : True
Issuer : CN=ex2016
NotAfter : 5/4/2023 1:00:52 PM
NotBefore : 5/4/2018 1:00:52 PM
PublicKeySize : 2048
RootCAType : Registry
SerialNumber : 6C9E5390A3A73392432EE62A45A483ED
Services : IIS, SMTP
Status : Valid
Subject : CN=ex2016
Thumbprint : 42A468A860EFF753DE8AD79D2FC575BAC7A4BED2
AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule,
System.Security.AccessControl.CryptoKeyAccessRule}
CertificateDomains : {WMSvc-SHA2-EX2016}
HasPrivateKey : True
IsSelfSigned : True
Issuer : CN=WMSvc-SHA2-EX2016
NotAfter : 5/1/2028 12:44:25 PM
NotBefore : 5/4/2018 12:44:25 PM
PublicKeySize : 2048
RootCAType : Registry
SerialNumber : 71BA83AE902DBEA846F0E5CF32607AC7
Services : None
Status : Valid
Subject : CN=WMSvc-SHA2-EX2016
Thumbprint : 874957BA59F383474BD40FB85B8C203D15F18C3A
[PS] C:\Windows\system32>