Hi

I have Exchange 2013 migrated from Exchange 2010

I have Event id:2005

Federation or Auth certificate not found: ED2C3E86EBE821AAC2C0DEA85CAB5787E2CAC5F3. Unable to find the certificate in the local or neighboring sites. Confirm that the certificate is available in your topology and if necessary, reset the certificate on the Federation Trust to a valid certificate using Set-FederationTrust or Set-AuthConfig. The certificate may take time to propagate to the local or neighboring sites.

I want to know what is the causes for this issue and how can I solve it ?

Hello

You need to search on old server for cert that thumbprint is ....
export with private key and import to new exch server and try repair trust
Get-FederationTrust | Set-FederationTrust RefreshMetadata

Already we uninstalling the old Exchange 2010 and migrate to 2013

how we can solve this issue

Hello

and haven't got any public cert like from godady or....

already i have from digitcert and it is working with no issue

but the thumprint shown in the event id is different , i dont know from where

Hello

plese run Get-FederationTrust |fl

Hello

empty?
from ecp org-->share is not enabled?

check adsiedt:
CN=Microsoft Federation Gateway,CN=Federation Trusts,CN=First Organization,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domain,DC=local

and remove entry if not need.

Hi Yasser,

The cause is that  the Certificate used by Authentication configuration is not exist on the server or deleted.

I recommend you refer to the following method to solve it :

Recreate a new Microsoft Exchange Server Auth Certificate by using the following command In EMS on the MBX server: 

1. Create a new certificate with SubjectName cn=Microsoft Exchange Server Auth Certificate

New-ExchangeCertificate -KeySize 2048 -PrivateKeyExportable $true -SubjectName "cn=Microsoft Exchange Server Auth Certificate" -FriendlyName "Microsoft Exchange Server Auth Certificate" -Services smtp 

Note: Do not accept to replace the SMTP certificate when prompted.

2. Note the thumbprint of the new certificate. We can use command Get-Certificate to retrieve all the cetificate information on the server.

3. Get the date of today, which will be used to set the new Certificates effective Date.

$a=get-date 

4. Configure the authentication configuration to use the new certificate and set the effective date.

Set-AuthConfig -NewCertificateThumbprint Certificate_Thumbprint in step2 NewCertificateEffectiveDate $a

Note: Accept to continue despite the fact that the certificate effective date is not 48 hours into the future.

5. Configure the certificate

Set-AuthConfig PublishCertificate

6. Make sure to remove any potential reference to the previous certificate (which might not exist anymore) by command:

Set-AuthConfig -ClearPreviousCertificate

7. Do iisreset on both CAS and MBX servers.

Best regards,

This is certificate coming from The old Exchange 2010 and we already uninstalled how we can remove this event id

still shown .